Puftups puff up in certain underwater areas when a Kong approaches these creatures. The puftups explode and release their spines after inflating too much air. These enemies aren't part of the Kremling crew even though these are bad characters.
Donkey Kong Country
The puftups aren't used in the final version of the game due to incomplete process of the enemy sprites. The puftups in the game's ROM have blue fins and an idle only animation.
Donkey Kong Country 2: Diddy Kong's Quest
Puftups appear in underwater levels such as Lava Lagoon, Glimmer's Galleon, Clapper's Cavern and other underwater levels. Their spikes protect themselves from being defeated by Dixie and Diddy Kongs even deflated. Enguarde the Swordfish must be used to defeat puftups even if they are inflated. The green and blue puftups over-inflate and explode therein the spikes fly in different directions. The green puftup's spikes fly in diagonal direction and the blue puftup's spikes fly straight up, down, left and right.
Donkey Kong 64
Puftups reappeared on Donkey Kong 64 acting the same way they've done in Donkey Kong Country 2: Diddy's Kong Quest. The puftups in this game purple and yellow. The puftups are found in Gloomy Galleon inside the ship and during the boss fight with Puftoss. These enemies are sent to attack Lanky Kong. They also appear in the King Kut Out boss fight surrounding the battle arena to keep the Kongs away from the water.
The enemies used for Donkey Kong 64 were re-used for Jolly Roger's Lagoon underwater areas as "Swellbellies" for Banjo-Tooie (which is the first game they've appeared that's not in the Donkey Kong series) but with pink, red and yellow coloring. The puftups inflate if Banjo or other character gets near these puffer fish. Unlike Donkey Kong 64, these fish will go near Banjo, Kazooie and the Submarine Banjo. The puftups can explode by a grenade egg or a submarine missile.
Donkey Kong: Jungle Climber
After 8 years of absence, the puftups reappear in the DS game "Donkey Kong: Jungle Climber", the puftups appear in several underwater stages. The only method to defeating puftups are using charge attack if they are deflated.