Ooze

Oozes are mindless, amorphous blobs that mostly dwell underground. They are essentially blind, but more than make up for that with an ability called blindsight, allowing them to discern nearby objects and creatures without needing to see them. Most oozes secrete an acid from their skin that dissolves flesh and other materials rapidly. They have a unique tendency to resist close-range and melee attacks by dissolving the wielder's weapon.