Vermin (Dungeons & Dragons)

In the Dungeons & Dragons fantasy role-playing game, vermin is a type of creature, or "creature type". Vermin can be any insects, arachnids, other arthropods, worms, and similar invertebrates, including giant versions of normal creatures. Most vermin are mindless.

All vermin have darkvision. Vermin are immune to all mind-affecting effects.

Vermin in the Monster Manual
The following are examples of vermin listed in the Monster Manual, one of the three core rule-books for Dungeons & Dragons.
 * Giant insects
 * Monstrous centipede
 * Monstrous scorpion
 * Monstrous spider
 * Swarms (centipede, locust, spider)