Acro

"This giant killer whale is the final boss of Aqua Star. He gets his name from his deadly underwater acrobatics."

- Description

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

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 his tailfins, then sliding at Kirby and crashing into one of the cave walls - knocking off a large boulder that can be inhaled and used as ammo against him.

After taking enough damage, Acro will destroy the cavern floor, in turn making Kirby and him 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 him by blowing bubbles at them. Anchors cannot be blown back and the mini-whales float up and down, making them difficult to push back. Once Acro reaches one of the walls, he will swim forward 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 his 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 he 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 him 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. He occasionally 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 sea floor as the cavern crumbles. The screen beings to scroll upward as he 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.

In the Super Smash Bros. series
Acro appears as a collectible sticker in Super Smash Bros. Brawl, using his artwork from Kirby 64: The Crystal Shards. He can be used on Peach and Zelda to strengthen their magic attacks.

Etymology
As stated in the Kirby 64: The Crystal Shards Prima guide, Acro's name comes from the word acrobat. His name is also orca backwards, a reference to his dolphin species.

Trivia

 * Acro was designed based on a female whale. This can be clearly seen when pointing out certain traits such as the dorsal fins. While Japanese sources do not give gender-specific pronouns and the games clearly show Acro spawning baby whales, the only official English source (the licensed Prima guide) indicates that it is male.
 * In the instruction manual for Kirby's Dream Land 3, Acro's name is spelled "Akro". This is most likely a spelling error, as his name is spelled correctly in the game.
 * In Kirby & The Amazing Mirror, a boss named Gobbler is believed to be the Mirror World counterpart of Acro.''
 * In the proposal documents of Kirby's Dream Land 2, an orca resembling Acro appears in a drawing showcasing the game's various characters (which also appears in the booklet included with Kirby's Dream Collection: Special Edition), yet this orca never appears in-game. This may hint that Acro was originally intended to appear in Kirby's Dream Land 2.
 * According to a pre-release screenshot's description, Kirby's inability to inhale Acro stems from a glitch in Kirby's genetic code.