Bats

Normal bats grown big. These animals aren't really aggressive, unless provoked, which can easily be done by moving too close to them. But they can be easily vanquished in combat.

In the Underworlds, we also met the more aggressive Vampire Bats, which are also much stronger.

Giant bats can be found in caves and dungeons, and sometimes at night in the wilderness.

Lore
''A non-evil subterranean dweller found in the deepest caverns, the principal diet of the bat is animal blood. They are quite large and may attack any who disturb their rest.''

- from "The History of Britannia, Ultima IV

''Equipped with keen hearing and night vision, these large, winged rodents are swift and efficient in their nocturnal attacks. Though difficult to hit, their fur-covered bodies are extremely vulnerable to damage.''

- from "Compendium", Ultima VI