These bags of air are rather simple lifeforms, floating around inside the lair of Bob the Killer Goldfish on La Planeta de Agua (Arriba!), for whom they appear to be the common foot soldiers. They have no discernible or distinguishing features, except for their trumpet-like tubes with which they expel disgusting blasts of air for locomotion and offense. It is unknown if they are aquatic creatures, since they are only seen floating within the air of the underwater base, and not actually in the water itself.
The puffer-fish are the only enemy in the level that Jim can actually defeat himself, without the help of the Hamster. Number Four and the mini-cats can be defeated with the Hamster, but the puffer-fish may actually pose more of a danger whilst riding the Hamster, as due to their movement patterns the Hamster may not be able to bite them and they may knock Jim off.
Puffer-fish are fairly easy to kill, taking only one blast from Jim's Plasma Blaster, upon which they collapse onto the ground with a big explosion of flatulent noise. However, in large numbers they can be quite a nuisance, and although rarely life threatening, are often found in groups. They can also be camouflaged quite well into the background, leading to Jim accidentally coming into contact with them.