Crew Battle is one of the gamemode available in Brawlhalla. It can be played in Custom Online matches and is sometimes available as the Brawl Of The Week. It was also used as the Seasonal Ranked Queue in Season 23.
This gamemode was added as part of Teenage Mutant Ninja Turtles Event, though has little to do with the crossover itself.
The Crew Battle gamemode is almost identical to a regular Team Stock battle; two teams face off to eliminate each other, the last team standing wins. What distinguishes this mode is only one opponent from each team is on the battlefield at a time. Once a player is knocked out, another player from the same team is brought on for the next stock. This can be changed in the game settings so that the next player on the team is only brought out once the first player has lost all their lives.
While this gamemode is intended for 4 players or more, it can be played with as little as 2 players. With only 2 players this gamemode is identical to the Stock gamemode.