Expert Negotiator is an Advanced Power card in Bloons Card Storm. It steals a 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 will instead delete the monkey it is used on. If successfully transferred to the player's side, any On Play effects the Monkey has will trigger again. The stolen Monkey is considered to be owned by the stealer; using Return to Sender will return the card to them instead.
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.
If your enemy's side is swarmed with bloons, you can steal a Thunder Druid to trigger its effect, provided your side still has space.
Be careful if you steal a Sun Temple, because the Sun Temple can sacrifice your monkeys on your side too. However, Sun Temple will gain up to +100 Damage if it sacrifices all four of your other monkeys.
An Expert Negotiator can counter an Expert Negotiator; it's a good way to get your stolen monkeys back.
After the stealing a Monkey, note that the opponent may have an Expert Negotiator to steal back a stolen Monkey. However, one of your Monkeys may be more valuable than that stolen Monkey.
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
Favored Trade can be used for freeing up space for Expert Negotiator. Other viable alternatives include Adora's sacrifice ability. Parting Gift also works, but is a very expensive combo.
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.
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)