When performed, Tails would put a small, blue and white mouse-shaped robot on the ground, which would immediately dash forward and explode on contact with an opponent. If it didn't touch anything, it would explode, after five seconds.
Chu² Bomb originates as a move used primarily by Tails in Sonic Battle, where it appeared as Tails' Ground Trap attack. When summoned, the Chu² Bomb will seek out the most nearby opponent and chase them, exploding upon contact.
The bomb released by Tails is very similar to a "Chu Chu" from ChuChu Rocket!, a game also developed by SEGA.