Pacto is a large, yellow creature with a large mouth, a single eye, and two yellow stubs jutting off its body. In Kirby's Dream Land 3, its red fangs show when its mouth is closed and the creature's eye lacks highlights. In all subsequent appearances, Pacto's mouth is wavy but contains its fangs, and its eye has highlights.
Pacto hides in a hole or open area, waiting for Kirby. When the hero passes by, the enemy quickly lunges out in an attempt to catch him in his mouth. He then spits Kirby out, damaging him. If the Pacto misses its mark, it recedes back to its original location and waits for another chance to strike.
Pacto's attack strategy is largely the same as in Kirby's Dream Land 3, only the enemy lunges out frequently even when Kirby isn't near. It also moves faster. Pacto is invincible as tapping it with the stylus does nothing.
Pacto's attack strategy is the same as in Kirby's Dream Land 3, only much slower. If Kirby is caught by the attack, the player must shake the Wii Remote or mash the +Control Pad to escape the enemy's mouth.
Pacto often takes multiple hits to defeat, but in exchange for this, Kirby can Super Inhale it. A white, cloudy variant of Pacto, called Pacloud, appears in Nutty Noon.
Pacto's behavior has not changed since Kirby's Return to Dream Land. A flowery variant, called Pacflower, appears in Wild World.
- The enemy Maw from Kirby 64: The Crystal Shards heavily resembles Pacto, and also has a similar attack pattern.
- Pacto and Dekabu are the only enemies in Kirby's Dream Land 3 to be instantly destroyed by the Ice ability. As larger foes, they would have required a larger ice block sprite to encase them. The developers of the game did not create such a sprite, which is likely the reason they cannot be frozen.
- Pacto's name, as well as its coloration and behavior, suggests that it may be based off Pac-Man, a famous video game hero.
- The design of Pacto's flowery variant that appears in Wild World appears to be somewhat based on Hearbell, an enemy that was cut from Kirby's Return to Dream Land.