Katsuyu

Katsuyu (カツユ, Katsuyu?) is the slug queen summoned by Tsunade. Compared to Gamabunta and Manda, the summons of Jiraiya and Orochimaru, respectively, Katsuyu is quiet and more subservient to her master. With her Slug Great Division (蛞蝓大分列, Katsuyu Daibunretsu?), Katsuyu can divide herself into smaller slugs to evade attacks or to serve small scale functions, and is able quickly reform herself if need be. She can also spit acid for her Tongue Tooth Sticky Acid (舌歯粘酸, Zesshi Nensan?), which is strong enough to melt through rock.

She is summoned again in a filler episode to mess with a pair of outsiders impersonating Might Guy and Rock Lee. In this instance, she had a cold and the two impersonators, along with a clueless Naruto, were forced to help out.

The name Katsuyu apparently comes from 蛞蝓, or slug in kanji, read in on'yomi.