Sluggula

Sluggula are tiny yellow slugs from The Minish Cap. Their tracks can be easily followed by the trail of slime they leave behind when they move across the room. Although some slugs can be seen slithering across a room when one first enters, some are very 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. They can only be fought when Link has shrunk to their size. They are slow and can be defeated in one blow. They are even easier to defeat when they are on their backs, just having jumped from the ceiling. It is debatable that the Torch Slug is an evolutionary offshoot of the Sluggula species, adapted to living in molten environments.

Quote from The Minish Cap Sluggula figurine:

"Appears in Minish dungeons. They drop from the ceiling unexpectedly. They are slow, so take your time, and defeat them one by one."

Trivia
An early beta version of Twilight Princess included what appears to have been a Sluggula, however this enemy was never included in the final version of the game. It may have been replaced by the Torch Slug.