Knuckles the Echidna (Sonic the Hedgehog Triple Trouble)

Knuckles the Echidna is the boss of Tidal Plant Zone. In this battle, Knuckles challenges the player in an underwater battle.

The battle is set entirely underwater, and as such, the player is susceptible to drowning. In this battle, Knuckles employs a strange, submarine vehicle as opposed to fighting the player one on one like he did in the last battle. The battle takes place on a scrolling screen as Knuckles moves backwards, firing at the player. Knuckles attacks by throwing two bombs that explode on impact, or by firing a torpedo forwards at the player. During the battle, Knuckles will rise off the screen at intervals to the surface to breathe, at the same time; an air bubble will conveniently rise from the ground, allowing the player to breathe. After Knuckles receives a certain amount of hits, his vehicle will explode and Knuckles will fall off the screen, defeated yet again.

When playing as Miles "Tails" Prower, Tails will use the Sea Fox for this battle, making the fight much easier as it allows the player to attack Knuckles from a distance.