Knuckles the Echidna (Sonic Adventure 2)

Knuckles the Echidna is fought as a boss in the Dark story of Sonic Adventure 2. He is fought by Rouge the Bat, after clearing Mad Space.

Battle
The battle takes place in the large tower seen in the center of Knuckles' stage, Meteor Herd. Knuckles will attack either through his Punch Attack, or by gliding and using the Drill Claw. Rouge must attack him when he lets his guard down. Eventually, the floor below the two will open, sending them into the air. The fight will continue on the sides of the tower when this happens, until the floor closes again. As Knuckles takes damage, he will begin to use two special moves depending on Rouge's distance from Knuckles. If she is a short distance away, then Knuckles will use his special move, the Hammer Punch, to stun Rouge. If Rouge is very far distance away, then Knuckles will use his super move, the Thunder Arrow. Four hits are required to defeat Knuckles.

Trivia

 * The fight against Knuckles in the Dark story is very similar to the fight against Rouge in the Hero story.
 * Along with Rouge, Knuckles is the only character boss not to be fought twice in the story.