Grimlet

Grimlets are enemies found within the Rusty Bucket's deck of Rusty Bucket Bay in Banjo-Kazooie. They are found stationary, disguising themselves as regular cowl ventilators and attacking Banjo and Kazooie once they get near. At distance, the only way to distinguish them from inanimate vents is by their colors, as Grimlets are a much lighter shade of gray.

Grimlets are one of the few enemies completely immune to any attacks, as even the Wonderwing will simply cause Banjo and Kazooie to bounce back.

Trivia

 * In earlier versions of Banjo-Kazooie, the Grimlets' eyes were located in their mouths.
 * Firing an Egg at a Grimlet causes a biting sound effect to play.