Sluggula

Sluggula are yellow slugs with blue stripes.

A Link to the Past
In, they first appeared in the Misery Mire dungeon, usually in small groups. They have the strange ability to lay green Bombs that can damage nearby intruders and prey, and will usually drop a large number of these while squirming around the room. Given this nature, they are invulnerable to explosives, so will not be harmed by their own bombs, but they are not particularly strong and can be destroyed by most other weapons quite easily.

Minish Cap
Sluggula return in, but in this game they are much more like normal slugs and are Minish-sized, and will therefore only appear in Minish dungeons and caves. They move much slower than their larger incarnation and no longer lay bombs. Their tracks can be easily followed by the trail of slime they leave behind when they move across the room. Although they can be seen slithering across a room when one first enters, some are more intelligent and wait on the ceiling for their prey to approach their vicinity, dropping down unexpectedly to deal damage. This attack can be avoided if one pay attentions to the shadows of the slugs under their feet. After falling, they will be on their backs for a short time, exposing a more vulnerable underbelly. If Link can catch them before they flip over, they can be defeated with a single sword strike.

Trivia

 * Sluggula's Japanese name is based on Nuranura (ぬらぬら), the Japanese word for "slimy".