This is a formidable enemy with a good amount of health, and decent but slow attack speed. A good method to defeat Mooths is to overwhelm it with fast-hitting units, like Cow Cat, or using Lizard/Gross Cat, since they outange it. It first appears in Empire of Cats Chapter 1, stage 38. This enemy is Floating, so anti-Floating cats are useful against him.
This enemy drops a large amount of money when defeated, and many stages later in the game use Mooths as a money provider.