Rotworms

Description
These worms are more of a nuisance than a real threat. Even the greenest warrior can destroy them without much trouble. Rotworms are neither strong in combat, nor poisonus, and thus easy vanquished.

They can be found in the swamps and in dungeons.

Evolution in the series
First appearance: Ultima V

Last appearance: Ultima Underworld II

They are the same in all installments in which they appear, but stronger in both Underworlds.

In both Underwolds, the Avatar also encountered the far more dangerous Blood Worms, a offshot of Rotworms.