Boss Bloon Event
Boss Bloon Events, also called Boss Events, are weekly events in Bloons TD 6 introduced in version 27.0 where players encounter Boss Bloons in a modified version of a Boss Challenge. It was introduced alongside the Boss Bloons' weakness, the Paragons. In each event, one of the Boss Bloons is selected to appear on a map, possibly with some challenge modifiers such as tower and hero restrictions. Victory is achieved in a Boss Bloon Event by defeating all five tiers of the boss before round 140 starts. The Elite version of the boss may not be attempted in single-player until tier 5 of the Normal boss is defeated.
Boss Bloon Events may be played in Co-op mode with up to 4 players. This event has an optional Ranked mode, which allows players to compete for spots on leaderboards and which may grant additional rewards depending on placement. Each leaderboard uses one of three scoring systems: Fastest Time, Least Cash, or Least Tiers.
While the event is active, players can access it by clicking on the Boss icon on the right of the Home Screen, via the Event menu or by selecting the featured boss in the Boss Challenge menu.
Schedule
The Boss Bloon Event usually runs weekly, starting Saturday at 02:00:00 UTC and ending Thursday at 03:00:00 UTC. There are sometimes exceptions to this schedule: for example, events typically end earlier right before a major update. Boss Bloon Events generally cycle between the seven available bosses in the following order: Bloonarius, Lych, Vortex, Dreadbloon, Phayze, Blastapopoulos and Diamondback. After an update that releases a new boss, these events feature the new boss for 4 weeks before returning to the regular order.
Since version 31.0, during the final hour of the event, players on Ranked Mode cannot start a new run, and those who are in the middle of a game will not be able to resume if they exit the game. This was done with the intention of preventing scores from being submitted past the ending time of the event.
While a Boss Bloon Event is active, the featured boss cannot be selected in Boss Challenge mode.
Mechanics
Boss Bloon Events are just a modified version of the Boss Challenge game mode, so it is natural that most, if not all mechanics from that game mode apply to Events.
Ruleset
Each Boss Bloon Event has a different ruleset, which determines many aspects of gameplay, including the type of Boss encountered and the map it is played on. In addition, there are many modifiers which may be in place during each event. Possible modifiers include those available in the Challenge Editor, plus some specific to Boss Bloon Events.
| Rule/modifier | Default value | Note(s) |
|---|---|---|
| Difficulty | Medium | Usually Medium, but Easy and Hard have all been used before in Boss Bloon Events. |
| Game mode | Standard | Usually Standard. CHIMPS, Half Cash, Alternate Bloons Rounds, Impoppable and Reverse have been used before in Boss Bloon Events. |
 Starting cash
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$650 ($850 with  More Cash)
|
Unlike in regular co-op mode, no additional starting cash is given in co-op Boss Bloon Events. |
 Starting lives
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200 in Normal, 100 in Elite | |
| Max lives
|
5000 | Hidden in-game. |
 Start round
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1 | Has been set as high as 39, but never higher. |
 End round
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140 | Always 140. However, if the player reaches round 140 without defeating the tier 5 boss, they lose instantly. The player wins by defeating the tier 5 boss, without needing to play up to round 140. |
 Max Monkeys
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Unlimited | |
 Max Paragons
|
4 | |
 Bloon speed
|
100% | Usually 120% if the boss is Vortex. |
 MOAB speed
|
100% | Usually 110% if the boss is Vortex. |
 Boss speed
|
100% | Has been set up as high as 2,500%. |
 Ceramic health
|
100% | |
 MOAB health
|
100% | |
 Boss health
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100% | Has been set up as high as 1,600%. |
 Regrow rate
|
100% | |
 Ability cooldown rate
|
100% | |
 Removable cost rate
|
100% | |
 Monkey Knowledge disabled
|
No | |
 Selling disabled
|
No | |
 Powers disabled
|
No (always Yes in Ranked mode) | |
 No continues
|
No | Boss Bloon Events use a different system than regular games, allowing the player to go back to the previous checkpoint at any time, or retry the last round when they lose. The game generates a checkpoint on rounds 20, 40, 60, 80, 100, and 120. |
 All Camo
|
No | |
 All Regrow
|
No | |
 Double Cash disabled
|
No (always Yes in Ranked mode) | |
 Fast Track disabled
|
No (always Yes in Ranked mode) | Using Fast Track allows the player to start on round 35 with $10,150 ($10,350 with More Cash).
|
| Leaderboard type | - | Only affects Ranked mode. One of Fastest Time, Least Cash, or Least Tiers. |
Boss Bloon Events may restrict possible Hero and Tower selections to a specific set, and restrict the quantity and upgrades of such towers.
Maps of all difficulties, including the special Protect The Yacht and Blons maps, have been used in events, but Beginner maps are selected most often. The Elite version of the boss may feature different leaderboard type, challenge modifiers and tower restrictions than the Normal version, but is always played on the same map.
Boss rounds
The general gameplay is the same as in Boss Challenge with the Tier 1 boss appearing on Round 40, and the successive tiers appear every 20 rounds until the final Tier 5 boss spawns on Round 120. A banner will be visible at the top of the screen indicating the number of rounds remaining until the boss appears, and while it is on the screen, the banner is replaced by the boss's health bar. Players receive rewards after beating each tier, but if the boss reaches the exit or is not beaten after 20 rounds since spawning, a defeat will occur even if no lives are lost. While the boss is on the screen, there are no breaks between rounds even if Auto Start is disabled. On most weeks the roundset will be the same as in Boss Challenge for the corresponding Boss, but custom rounds have been used in the past and are set server-side.
Checkpoints are saved at Round 20 and every 20 rounds after. Players can return to the last one by paying some Monkey Money. The cost starts at 
100 and increases by an additional 100 every 20 rounds. If the player is defeated they may also choose to restart at the last check point or also retry the last round by paying twice the amount of the 20 round checkpoint. Exiting the the game and returning only restarts the current round with no additional penalties.
Co-op
Boss Bloon Events can also be played in Co-op mode within public or private lobbies. The rules for cash sharing are the same as in regular Co-op modes. Unlike regular Co-op, no additional starting cash is granted, and the map split is always free-for all.
In this mode, the health of the boss is increased by 20% for each additional player (+20% for 2, +40% for 3 and +60% for 4 players). The rewards for beating each tier are the same as in solo, given in full to each player in the team, and can't be earned after having already done so in solo.
Ranked Mode
Before starting a game, players may check a box in the lower left part of the screen to play in Ranked Mode, in which players compete to place as high as possible on a leaderboard for additional prizes. This mode disables Insta Monkeys, Powers, in-app purchases (such as Double Cash or Fast Track) and Perks to prevent pay-to-win scenarios. Everything else regarding to the event (Boss, Map, modifiers and restrictions) is the same as non-ranked mode.
Scoring
There are three scoring types, and in all of them a lower score is better:
- Fastest Time: A timer starts the moment a Boss Bloon enters the screen, keeps running until is defeated, and resumes every time the boss returns on later tiers.
- Least Cash: A counter is increased by the amount of cash spent when a tower is placed or an upgrade is purchased. Paying cash to purchase items at Geraldo's Shop, using map features such as removing obstacles or gizmos or using the cash slider when creating a Paragon also increases the score accordingly.
- Least Tiers: A counter is increased by one every time a tower is placed or a upgrade is purchased including Hero levels and Paragon upgrades. Gizmos and Sub-towers such as Geraldo's shop items or the Marine deployed by the Special Poperations ability do not increase the score.
There is no way to reduce the amount of score already accumulated.
Least Cash and Least Tiers also keep track of the player's time, which is used as a tiebreaker between players with the same amount of cash or tiers spent. If players have exactly the same score including tiebreakers, then ties are broken by time of completion in favor of scores submitted earlier.
There is also a penalty timer (shown in red below the boss banner/health bar) that penalizes players for taking too long to beat non-boss rounds. Every round, 10 + Round Number × 0.25 seconds after the last Bloon of a round enters the screen, a timer begins to count up until all Bloons from that round are popped. At the end of the game, all accumulated time in the penalty timer is added to the regular Boss timer. The cooldown of cash-generating abilities is paused while the penalty timer is active, even in non-Ranked mode (where the timer does not appear), to prevent abuse and weaken strategies based on income-generating abilities like IMF Loan or Supply Drop.
Leaderboards
Every week, one of the three scoring types is selected for Normal and Elite and all players who defeat the boss will be ranked according to it. The scores for Normal and Elite bosses are independent from each other, and since version 44.0, they can have a different scoring type on the same week. Regardless of the type used, the timer described above will appear because it is used as the tie-breaker in Least Cash and Least Tiers rankings.
Ranked Mode can also be played in Co-op mode and the scores of each size of team is recorded in an independent leaderboard (there are different rankings for teams of 2, 3 or 4 players). If a player has scores in multiple leaderboards for the same Boss difficulty, only the highest prize will be earned.
In addition to the global ranking, players who defeat the boss in Ranked Mode are placed automatically in a smaller leaderboard with pool of up to 100 players (in a first-come, first-served basis) known as the Mini-Boss. Players can gain additional prizes based on their ranking within the Mini-Boss. Co-op and solo players may be placed in the same Mini-Boss.
Strategy
Boss Bloon Events are usually harder than Boss Challenges, due to modifiers and restrictions that can be applied each week, but in general, strategies for Boss Challenges can also be applied to Boss Bloon Events.
The most important advice for defeating Bosses, especially Elite versions, is to generate additional income (a.k.a. farming) and start doing so as early as possible. Normal Bosses can sometimes be beaten without additional income and a proper defense strategy, but Elite Bosses are simply impossible without farming. Benjamin and Geraldo are the most used Heroes in Boss Bloon Events thanks to having methods of generating extra income that can be used to accelerate early game farms. Other heroes with an early game carry or buffing potential are used when both of these heroes are banned.
More details for the gameplay between tiers can be found in the main Strategy article. Strategies to defeat the boss itself are found in the strategy page for each Boss Bloon: Bloonarius, Lych, Vortex, Dreadbloon, Phayze and Blastapopoulos.
Rewards
|
The information in this article or section is specified server-side and can be changed by the developers at any time without warning. This information may become out-of-date at any time without notice. This information was last verified as up-to-date on: 10 October 2025 |
For defeating tiers
| Tier | Normal | Elite |
|---|---|---|
| 1 | 50
|
100
|
| 2 | 50
|
100
|
| 3 | 75,  ×1
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150,  5,  ×1
|
| 4 | 100, 5,  ×1,  Tier 2 ×1
|
200, 15,  ×1,  Tier 3 ×1
|
| 5 | Default: 125, 25,  ×1, Tier 3 ×1Collection Event: 125, 25,  35, Tier 3 ×1
|
Default: 250, 50,  ×1,  Tier 4 ×1Collection Event: 250, 50, 70, Tier 4 ×1
|
Ranked leaderboard
| Position | Normal | Elite |
|---|---|---|
| 1st | 1,000, 40,  "Best" Power ×1,  Tier 5 ×1
|
1,000, 60, "Best" Power ×1, Tier 5 ×1
|
| 2nd | 750, 35, "Best" Power ×1, Tier 4 ×1
|
750, 50, "Best" Power ×1, Tier 4 ×1
|
| 3rd | 500, 30, "Attack" Power ×1, Tier 4 ×1
|
500, 40, "Attack" Power ×1, Tier 4 ×1
|
| Top 50 | 450, 25, "Attack" Power ×1, Tier 3 ×1
|
450, 30, "Attack" Power ×1, Tier 3 ×1
|
| Top 100 | 400, 20, Tier 3 ×1
|
400, 25, Tier 3 ×1
|
| Top 10% | 300, 10, Tier 2 ×1
|
300, 15, Tier 2 ×1
|
| Top 25% | 200, 6,  Tier 1 ×1
|
200, 10, Tier 1 ×1
|
| Top 50% | 100, 3, Tier 1 ×1
|
100, 5, Tier 1 ×1
|
| Top 75% | 50, 2, Tier 0 ×1
|
50, 3, Tier 0 ×1
|
Mini-boss leaderboard
| Position | Normal | Elite |
|---|---|---|
| 1st | 500, 15, Tier 4 ×1
|
500, 20, Tier 4 ×1
|
| 2nd | 400, 10, Tier 3 ×1
|
400, 15, Tier 3 ×1
|
| 3rd | 300, 5, Tier 3 ×1
|
300, 10, Tier 3 ×1
|
| Top 10% | 250, 3, Tier 3 ×1
|
250, 5, Tier 3 ×1
|
| Top 25% | 150, 2, Tier 2 ×1
|
150, 3, Tier 2 ×1
|
| Top 50% | 100, 1, Tier 1 ×1
|
100, 2, Tier 1 ×1
|
| Top 75% | 50, 1, Tier 1 ×1
|
50, 1, Tier 1 ×1
|
Medals
Ranked Mode
Ranked Mode medals are awarded based on the player's position on the global leaderboards once the event ends.
-
Boss Event - Top 75% -
Boss Event - Top 50% -
Boss Event - Top 25% -
Boss Event - Top 10% -
Boss Event - Top 100 -
Boss Event - Top 50 -
Boss Event - 3rd -
Boss Event - 2nd -
Boss Event - 1st
-
Elite Boss Event - Top 75% -
Elite Boss Event - Top 50% -
Elite Boss Event - Top 25% -
Elite Boss Event - Top 10% -
Elite Boss Event - Top 100 -
Elite Boss Event - Top 50 -
Elite Boss Event - 3rd -
Elite Boss Event - 2nd -
Elite Boss Event - 1st
Boss Bloons
Boss medals are earned by popping all five tiers of the corresponding Boss Bloon. This doesn't require playing in Ranked Mode.
-
Boss Event - Bloonarius -
Boss Event - Bloonarius - Elite -
Boss Event - Lych -
Boss Event - Lych - Elite -
Boss Event - Vortex -
Boss Event - Vortex - Elite -
Boss Event - Dreadbloon -
Boss Event - Dreadbloon - Elite -
Boss Event - Phayze -
Boss Event - Phayze - Elite -
Boss Event - Blastapopoulos -
Boss Event - Blastapopoulos - Elite -
Boss Event - Diamondback -
Boss Event - Diamondback - Elite
Update history
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- Leaderboards for co-op boss events will now be able to display up to a 100 total ‘teams’ for each category rather than just 100 ‘players’ for each
- Added a 1 hour cutoff where no new ranked games can be created and existing ranked games cannot be entered
- If the player is already in a ranked game during this cutoff the score can still be submitted to the leaderboard as long as the player does not exit out of the game
- Changes to Boss auto-play behavior
- if a Boss or its spawn are on screen the game & next round always starts immediately
- If a Boss is not on screen then the game does not start automatically
- If auto-start toggled off then the game will stop between rounds
- Added a new checkpoint at round 20 for boss events
- Resolved an issue with Boss checkpoint costs being pulled down causing T5 boss checkpoint to be free (bug fix)
Loading a profile from the cloud will no longer keep boss event saves
- Boss Events now support multipliers to Boss Speed & Boss HP as an event rule
- Boss Events now support paragon count limits as an event rule
- Added a Retry Last Round ‘continue’ option for CT & Boss for a MM cost with no bonus cash granted
- Boss Speed/Health edits have event modifier icons
- Added a spicy new indicator to the main menu background for when a boss event is active
- Resolved an issue that could count Dreadbloon’s timer incorrectly after boss death (bug fix)
- Bosses fail the player 19 rounds after the boss spawn instead of 20
- Note: This also fixes the restart from checkpoint bug putting the player in the next checkpoint with no boss.
- Fixed issue with retrying during Boss fights (bug fix)
- Resolved issue with checkpoints if Boss not defeated within a certain number of rounds (bug fix)
- Resolved an issue with Boss Checkpoints not being offered if taking 20 rounds to lose to a boss (bug fix)
- Resolved an issue with Boss co-op lobbies not respecting main boss menu ranked checkbox option (bug fix)
- Resolved an issue that could allow guest accounts to load into co-op event lobbies (bug fix)
Resolved an issue with Bosses scaling their health both from Boss & MOAB multipliers (bug fix)
Added Retry Last Round functionality to co-op Boss events- Resolved a number of Boss HP scaling inconsistencies (bug fix)
- Resolved an issue where T5 bosses would defeat the player earlier than intended (bug fix)
- Bosses on spawn will now clear the map of all existing projectiles
- Refactored how leaderboard scores are stored so that we could add Least Cash/Tiers ranking options for Boss Events
- Added an event icon to display if a Paragon Limit is being applied to events
- Added further support to grant events more flexibility in Boss starting and finishing rounds
- Behind the scenes maintenance on Boss leaderboard score processing
- Resolved an issue with Defeat UI being closed when Bosses leak in co-op
- Boss Event and CT Boss default Penalty Time changed ― 10s → 10 + round number * 0.25
- While Penalty time is counting in Boss Events and CT Boss, cash generating abilities will stop cooling down
- Note: This will also occur in unranked Boss Events despite the absence of the penalty timer
- Resolved an issue with low damage numbers not performing calculations correctly against exceptionally healthy targets (Bosses) (bug fix)
Solved a game crash that happened when a player defeats the Tier 5 Boss Bloon without having the corresponding Boss Medal beforehand.
- Co-op: Default map split now set to Free-for all.
- Scores will now appear on the Leaderboard after beating the Tier 1 Boss instead of the Tier 5, however, victories on lower tiers will always be ranked lower than higher tiers.
- Top 1% medal is changed to Top 100.
- Paragon limit is now applied per player and not globally
- Diamondback is now available
- Players now only need to beat the Normal difficulty once to unlock the Elite version in the current and all future events featuring the same Boss
- Projectiles no longer spawn sub-projectiles when destroyed by the Boss Bloon entrance
- Note: This is an overall nerf for towers such as the Mega Massive Munitions Factory
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