Cabbage slug

This tiny slug, able to quickly reproduce, can destroy entire cabbage patches in less than a week. These pests are sometimes hard to spot because they bore holes into the cabbages and eat them from the inside out - by the time you realize they are there, it can be too late. During "The Serpent's Pass", it is said that a single cabbage slug could destroy the entire ecosystem of Ba Sing Se, and becasue of which the cabbage salesman's cabbages were confiscated and destroyed.