Boss Challenge

Boss Challenge icon in the Events menu

Boss Challenge is a game mode in Bloons TD 6 involving Boss Bloons introduced in version 40.0. In this mode, players can challenge Bloonarius, Lych, Vortex, Dreadbloon, Phayze, Blastapopoulos, or Diamondback on any map of their choice, including Protect The Yacht and Blons. This mode features no rewards but can be played for the challenge alone, to improve the player's own scores or can be used as practice for Boss Bloon Events.

Players can access this mode by going into the Events page and clicking on the corresponding button in the lower left part of the screen.

Mechanics

Ruleset

Players can choose any of the Boss Bloons, the featured and Map for the challenge. The game mode is always set to Medium difficulty and uses rounds 1–140 of the boss's custom rounds. The player starts with 200 lives for Normal bosses, or 100 for Elite bosses. All Towers and Heroes can be used in this game mode. All other challenge rules are set to their defaults.

On round 40 the Boss spawns in a fixed point near the entrance (each Boss has a themed visual of its spawning point) and will start moving. While the Boss is on the screen there will not be breaks between rounds, even if Auto-start is off.

If the Boss is defeated, it will return again in Round 60 with much greater strength and this will be repeated in Rounds 80, 100 and 120. Each of these five stages is known as a Tier. The tier will be indicated above the Boss' Health bar with some stars.

To achieve Victory the player must defeat the Tier 5 boss and the game will end at the end of the round where this Tier is defeated (it is not necessary to keep playing until Round 140). The player will be defeated if all lives are lost, if the Boss reaches the exit or if the Boss is not defeated within 20 rounds since spawning.

All the bosses also have a harder difficulty available, known as an Elite Boss, with much higher Health and stronger abilities.

If there is a Boss Bloon Event active, the featured Boss cannot be selected in Boss Challenge and instead there will be a button in the Boss Challenge menu to go to the Boss Bloon Event.

Rounds

The game starts at Round 1 and the gameplay will be the same as a game of Medium until Round 39. A banner in the top of the screen will indicate the number of remaining rounds before the Boss appears. Once the boss has spawned, the banner is replaced by the boss' health bar and anything else related to it, like special properties. On round 40 the Boss appears in a fixed point near the entrance (each Boss has a themed visual of its spawning point) and will start moving in that track. While the Boss is on the screen there will not be breaks between rounds, even if Auto-start is off.

Rounds where the Boss spawns have different Bloons than the standard set (hence the custom rounds rule), for most Bosses, with the exception of Dreadbloon, the changes are:

Round	Changes
40	MOAB replaced by 6 Ceramic Bloons
60	BFB replaced by 6 MOABs
80	ZOMG replaced by 6 BFBs
100	BAD replaced by 4 ZOMGs and 6 DDTs

Bloonarius, Phayze and Blastapopoulos have no further changes. Lych, Vortex and Dreadbloon feature changes on other rounds as well (see the page of each boss for details).

The game is saved after every round like any other standard game mode, but only one save is conserved per Boss. In addition to this, the game will also conserve a checkpoint at Round 20, 40, 60, 80, 100 and 120 that the players can return to by paying some Monkey Money. The cost starts at  25 and increases by an additional  25 every 20 rounds. If the player is defeated they may also choose to restart the last round by paying twice the amount of the 20 round reset. Exiting the the game and returning only restarts the current round with no additional penalties, notice that if the Boss is active, the game will resume immediately upon loading.

Boss Path

If the map only has one path or a designated one for MOAB-Class Bloons (except on Quiet Street), the boss will use it, otherwise one of the available paths will be the designated boss path which is fixed in any playthrough, and will use it even if would not be normally used on the round it spawns. For example, in Bloody Puddles, the boss will always appear in the middle track moving from top to bottom. Bloonarius Prime and Ancient Portal have exclusive paths for the bosses.

The paths the bosses will use are the following:

This article is in need of research. You can help out by editing this article or discussing your findings on the talk page. The editor who added this notice elaborates: Information on Balance might not be accurate, boss can switch to other paths.

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  Lost Crevasse - Center
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  Luminous Cove - Left
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  Water Park - Lazy river (Lower)
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  Polyphemus - Top to bottom
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  Quiet Street - Top to bottom Bloon path, it does not use the MOAB-Class Path.
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  Bloonarius Prime - Starts in the left doing the loop, then crosses over the rocks to the right path, right next to the portal.
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  Balance - Right to left, can switch between the 4 different paths.
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  Encrypted - Left to bottom right
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  Bazaar - Top
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  Adora's Temple - Left to right
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  Spring Spring - Top
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  Haunted - Left to right
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  Firing Range - Top left to bottom right
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  Chutes - Left
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  Rake - Left
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  Party Parade - Left
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  Enchanted Glade - Bottom
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  Last Resort - Straight shortest path.
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  Ancient Portal - Starts from the lower right, crossing over the portal to the left path.
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  Castle Revenge - Top
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  Erosion - Middle
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  Midnight Mansion - Top left to center right
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  Sunken Columns - Right
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  Underground - Top
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  X Factor - Top left to bottom right
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  Mesa - Lower
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  Spillway - Top left to top right
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  Pat's Pond - Top
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  High Finance - Odd (top right to bottom left)
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  Tricky Tracks - Middle rails, right side (bottom left to top right)
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  Dark Dungeons - Middle
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  Sanctuary - Top left to middle right
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  Ravine - Top right to middle left
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  Infernal - Top
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  Bloody Puddles - Middle, top to bottom
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  Quad - Left to right
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  Dark Castle - Top
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  Muddy Puddles - Middle left
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  #Ouch - Horizontal top
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  Protect The Yacht - Left

Battle Mode

The player can enable the Battle Mode by checking a box in the right side of the screen, which disables Double Cash Mode, Fast Track Mode, and Powers. In addition to that, the player must select one of three scoring types: Fastest Time, Least Tiers or Least Cash. The game will keep track and record all 3 scoring types after beating each tier, but will only show to the player the selected one during the game.

For further information on how the scoring system works consult the Scoring section of Boss Bloon Event.

Score tracking

In the Boss Challenge menu, the user interface will show a skull icon that indicates if a Boss has been beaten or not on the currently selected map, regardless if Battle Mode was active or not. Each map and boss difficulty (Normal / Elite) are tracked separately.

If the players selects Battle Mode the menu will show the the highest tier beaten and best scores for Fastest Time, Least Cash and Least Tiers scoring types. On all three types a lower score is considered better; however, any score on a higher boss tier will always be considered better one of a lower tier, regardless of the specific score. For example, beating a Tier 2 Boss with a 20 minutes Fastest Time score will always be considered better than a 10 second Tier 1 score.

Additionally the map selection menu will show a skull icon on the top right corner of maps where the currently selected Boss has been defeated, with a blue background for Normal and purple background for Elite. Both icons will show if both difficulties have been beaten.

Strategy

For more in-depth strategies, see Strategy:Boss Bloon Event.

Defeating a Boss Bloon is a difficult task for players used to the regular game modes, especially on Elite difficulty, as it requires a different approach to handle their health and abilities. In general heavy farming and starting as early as possible is a requirement because expensive towers, Paragons and tower spam strategies are common ways to defeat the Bosses.

Before Tier 1 farming is handled by spending as little cash as possible to defend the regular rounds to use all the cash for farming setups with Marketplace spam and IMF / Monkeyopolis being common strategies supported by towers like Bloon Trap, Rubber to Gold and Heroes like Geraldo and Benjamin for extra income. These strategies are enough to afford towers like Elite Defender or The Blazing Sun to defeat the Tier 1 Boss.

After that, the usual farming progression involves selling the Boss defense to afford an Overclocked Banana Research Facility and use it to progress into a Banana Central or Merchantman + Central Market setups on water-heavy maps, ability-based income from Support Chinook, Jungle's Bounty or Monkey-Nomic can also be used if the player can stall the rounds.

Usual towers which can defeat the Tier 2 Bosses include M.A.D or Avatar of Wrath without forgetting tower spam strategies like Overdrive, Plasma Monkey Fan Club, Destroyer or Spike Storm, all of those with helped with usual support towers like Embrittlement, Glue Strike, Cripple MOAB, Stronger Stimulant or Jungle Drums and Call to Arms (and higher upgrades).

Farming for Tier 3 and higher is achieved by filling the map with Banana Research Facilities and constantly using Overclocks on them and for the defense Paragons are heavily recommended, (Apex Plasma Master, Glaive Dominus and Crucible of Steel and Flame can usually be afforded for Tier 3, Navarch of the Seas, Nautic Siege Core, Ascended Shadow and Master Builder for Tier 4, and finally Goliath Doomship, Magus Perfectus, Mega Massive Munitions Factory or even a VTSG can be used for Tier 5. In most cases Tier 5 Normal and Tier 4 Elite Bosses can require a two Paragon defense and Tier 5 Elite needs 3 or even 4, depending on the map and the Paragon degree.

Consult the Strategy section of Boss Bloon Event for more advice, as both game modes are extremely similar, what works in events is very likely to be useful for Boss Challenge as well. If looking for information for a specific Boss consult their strategy pages: Bloonarius, Lych, Vortex, Dreadbloon, Phayze, Blastapopoulos, and Diamondback.

Update history

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Version 48.0

• Co-op: Default map split now set to Free-for all.
• Co-op: Map split can now be changed.
• The game will now keep track of the highest tier which has been defeated.

Version 51.0

• Paragon limit is now applied per player and not globally

Version 54.0

• Diamondback is now available

Version 55.0

•  Corrected Lych's roundset within Boss Challenge mode
• 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

Gallery

Screenshots

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  Normal Bloonarius has not been defeated on Monkey Meadow.
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  Elite Bloonarius has been defeated in Monkey Meadow.
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  Normal Dreadbloon defeated in Spice Islands in Battle Mode, showcasing the scores for the run.
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  Ongoing run of Elite Dreadbloon in Another Brick, showing the partial scores obtained up to Tier 3.
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  Map selection menu, Normal difficulty is cleared in Monkey Meadow, Elite on Tinkerton and both in Spa Pits.