|“||This giant killer whale is the final boss of Aqua Star. He gets his name from his deadly underwater acrobatics.”|
|— Description • Kirby 64: The Crystal Shards Official Strategy Guide (Prima)|
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 on Aqua Star. He is not evil, however, as his appearances show him to be under the influence of Dark Matter mischief.
Acro is the boss of Ripple Field, having been disturbed by Dark Matter. 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 skulls, anchors, and Acro Jrs., which Kirby must push back at him by blowing bubbles at them. Anchors cannot be blown back and the Acro Jrs. 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 freed of Dark Matter and 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.
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 backflip 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. His sticker can be used on Peach and Zelda to strengthen their magic attacks by 15.
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 species.
- Acro's design was based on a female killer 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 he is male.
- In the instruction manual for Kirby's Dream Land 3, Acro is listed as "Akro the Whale." This is most likely a spelling error, as his name is spelled correctly in the game.
- 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 assimilate (or inhale) aquatic predatory mammals (ie. Acro) stems from a glitch in Kirby's DNA.
- Despite this, at the end of Boss Endurance, Kirby is seen with a Copy Ability that is a mix of every boss in the game, including Acro.
- Mech Acro, an enemy from Kirby: Planet Robobot, is based on Acro in appearance.
- HR-H, Acro, and Whispy Woods are the only bosses in Kirby 64: The Crystal Shards to remain in one piece when defeated.