Swellbelly

Swellbelly is a large blowfish enemy which inhabits the depths of Jolly Roger's Lagoon. It reacts to threats by puffing itself up to an enormous size, piercing anything that gets too close with the sharp spines that cover its body.

Swellbellies can be easily defeated by using the Talon Torpedo or by firing Grenade Eggs at them once Banjo and Kazooie learn how to use Sub-Aqua Egg Aim Egg Aiming underwater.

Trivia

 * Swellbellies are recycled from the Donkey Kong Country enemy "Puftup".