Acid Slugs

Acid Slugs are basically huge slugs. What makes them dangerous, their name already says. They attack any being they sense near them them with a strong, poisonous acid, which can destroy weapons and armor and cause horrible burns on the skin. Acid slugs however are very susceptible to fire, and a lit torch is most times already enough to destroy them.

Acid slugs are only found in dungeons, caves and swamps.

While their behavior is always the same, the looks of the Acid Slugs changed quite often. In Ultima VI, they looked like pink blobs. In the Underworlds, they looked like green slugs. In Ultima VII and VII/2, they looked like white slugs.

Lore
''Slugs are little to be feared, only avoided. They writhe mindlessly and senselessly from place to place, feeding on whatever they encounter. Disgustingly enough, the flesh slug is a large amorphous blob of gelatin, the color of pale pink human flesh. The greenish acidslugs are slightly more dangerous, as they are capable of spitting acid a considerable distance.''

- from "A Safe Passage Through Britannia", Ultima Underworld II