A Power Battle is a special fight that is held between two opponents, the challenger and the challengee, however one person can challenge two (and possibly more) people to a power battle.
Power battles can happen for any number of reasons, but they are always initiated by the challenger shouting "Power battle!" After finishing the phrase, a power battle will begin and seemingly cannot be ended or backed out from until the fight is over.
Known Power Battles
When K.O. realized who the graffiti wiener was that vandalized the plaza sign, K.O. stepped out into the plaza and initiated a power battle, something he had tried to do earlier, but failed. After a crowd gathered, K.O. explained that he knew that the graffiti wiener was a Boxmore spy. While possibly not done intentionally, Radicles appeared to be the opponent, up until K.O.'s Power-Fist Fireball veered around Radicles and hit a suspicious, hooded man, who was revealed to be Darrell.
Carol calls upon a power battle between the two when Chameleon Sr. insulted K.O., which results in the two battling. Carol grabs Chameleon Sr. by the tongue and starts to repeatedly punch him while pulling him back to her when he falls back, however Senior pulls his tongue back which makes Carol slam her into the roof. Chameleon Sr. then gloats about how she is a coward, however, unbeknownst to him, she grabs his tail, spins him around, throws him into the air, then kicks him back down onto the roof. While Carol tells K.O. that her work is done, Senior breaks out of the rubble and grabs her with his tail and throws her onto the parking lot. While Carol is laying in the crater, Chameleon Senior does a belly-flop onto her. He grabs Carol and continues to fling her around in his tail. The battle ends when K.O. tries to offer him some Dragon-Dragon Burritos, but to no avail, Chameleon Senior eats K.O., who drops the burritos down his stomach, and fills Senior's mouth in fire. K.O. escapes and pulls off Chameleon's suit.
The battle starts when Lad Boxman throws a box at Mr. Gar, who then pursues Boxman. The two run up to each other, which results in Mr. Gar elbowing Lad Boxman so hard, he was able to see the curvature of the planet. Boxman then landed on the other side of the road, where Boxmore was then built.
It is unknown how the battle started between the two, but we see them battling outside of the Fitness Dojo, with Vormulax attempting to claw Shy Ninja. Eventually, Shy Ninja gets the upper hand towards Vormulax, as she teleports and kicks her onto the pavement. Vormulax accepts her defeat, then tells Shy Ninja to go ahead and gloat.