Acro

Acro is a boss character that appears in Kirby's Dream Land 3 and Kirby 64: The Crystal Shards. She is a large orca whale that currently lives in a deep sea trench in Aqua Star. She is not entirely evil however, as she was under the control of Dark Matter. Her name is in fact Orca spelled backwards, and short for acrobat, which describes the swift flipping motions she makes while fighting Kirby underwater.

She also appears as a collectible sticker in Super Smash Bros. Brawl, using her artwork from Kirby 64. It can be used on Peach and Zelda to strengthen their magic attacks.

Kirby's Dream Land 3
Acro is the boss of Ripple Field, having been disturbed by King Dedede. The battle starts off in a cavern with Acro walking on her tailfins, then leaping at Kirby and crashing into one of the cave walls - knocking off a large boulder that can be inhaled and used as ammo against her.

After taking enough damage Acro will destroy the cavern floor, in turn making them both plunge into the water below where the rest of the fight takes place. Acro swims back and forth spitting out various objects like anchors, skulls and even baby whales, which Kirby must push back at her by blowing bubbles at them. Anchors cannot be blown back and the mini-whales float up and down, making it difficult to push back. Once Acro reaches one of the walls, she will swim foward at great force, crashing into it and creating a large undersea avalanche. Kirby has the chance to drive these falling rocks back at Acro as he simultaneously dodges the rest.

If all the Heart Stars are collected for Ripple Field, Acro will be cured of her anger and become friendly the next time Kirby enters the arena.

In Boss Butch, the battle takes place outdoors, possibly below a sandstone cliff, as seen in the first phase of the battle.

Kirby 64: The Crystal Shards
Acro, who relocated on Aqua Star, gets disturbed again when she somehow stumbles across a Crystal Shard in the water. The battle starts off much like the second phase did in Kirby's Dream Land 3 ; Acro shoots out the same objects as before that must be shot back at her to cause damage. Now, however, Kirby has the luxury of inhaling them, and no longer needs to precariously shoot bubbles at them to send them back. Occasionally she will do an underwater back flip and crash into the ground, creating two rocks that can be inhaled and shot back.

After enough damage is dealt, Acro retires to the seafloor as the cavern crumbles. The screen beings to scroll upward as she chases Kirby to the surface. Kirby encounters more enemies to inhale as Acro darts round shooting out Pedos. After Kirby lands the finishing blow, Acro sinks out of sight, leaving Kirby the Crystal Shard.

Acro's card is #4 on page 1/9.

Trivia

 * Acro backwards is orca, which is the animal that the boss is based off of (particularly a female).
 * In the instruction manual for Kirby's Dream Land 3, Acro's name is spelled "Akro". This is most likely a spelling error, as her name is spelled correctly in the game.