Expert Negotiator is an Advanced Powercard in Bloons Card Storm. It steals a target Monkey from the opponent's side and moves it to the player's side. If the player already has all 5 monkey slots filled, then Expert Negotiator instead removes the monkey it is used on. If successfully transferred, the Monkey is always placed on the available slot closest to the bottom, and if this Monkey has On Play effects, then they trigger again. The stolen Monkey is considered owned by the stealer; using Return to Sender will return the card to their hand, but Card Backs from the original owner will be retained.
Expert Negotiator is best used if your side has space, so you can take advantage of the monkey you stole. Otherwise, it is just a more expensive Shrink that lacks a Baby Monkey.
Re-playing the On Play effect is best used on Bloon Master Alchemist and MOAB Dominator. It's okay on Thunder Druid, but many other cards are better board clears, so only steal this if you've got no better options in your hand.
Be careful before stealing Monkeys that forcibly modify your Monkeys if your side still has space. Avoid stealing Sun Temple and Total Transformation Monkey if your side has valuable Monkeys.
An Expert Negotiator can counter an Expert Negotiator; it's a good way to get your stolen monkeys back.
Note that an opponent counterplaying an Expert Negotiator may steal one of your more valuable Monkeys instead of their recently stolen Monkey.
Freeing up a Monkey space for Expert Negotiator is difficult, as filling board space is necessary to survive without much risk. Adora's sacrifice ability, and Salvation (also exclusive to Adora), and Favored Trade are some effective options.
Other cards are less recommended but still work. Parting Gift is a generally weak card, Return to Sender is better used to counter enemies or return own Monkeys with valuable On Play effects, and Temporary/Doomed Monkeys require another turn to open a Monkey space.
Enemy cards such as Bed Time or Expert Negotiator, or Amelia's Grand Disappearance, or in some cases a Toxic Bloon popped by one of your Monkeys, can also open a Monkey space for Expert Negotiator.
Expert Negotiator is an expensive power. If the opponent is currently playing aggressively, stealing a Monkey that lacks defense or ammo on the current turn is unwise. Likewise, Expert Negotiator is virtually useless against aggro because most aggro decks have few or no Monkeys.
Expert Negotiator is completely useless against Bosses, as they cannot run Monkeys.
Many control decks bring Expert Negotiator to prevent the opponent from capitalizing on their Monkeys, as well as benefit the player.
Keep a note of how many Expert Negotiators the opponent used; if they already used all 3, they will be forced to use other monkey removals to neutralize their stolen Monkeys.
When Expert Negotiator is used, the Sun Temple no longer copies the attack power gained from the original sacrifice, instead it gains power equivalent with the amount of monkeys sacrificed on the side of the Expert Negotiator user (bug fix)