The Shrinking Slug Fiend is a small, purple, two-eyed fiend created by Vendetta as another attempt to destroy Charlotte.
The Shrinking Slug Fiend was made by Vendetta off-screen and was introduced to Charlotte in "Shrinking Charlotte" in the television version, and in web episode 7. The Shrinking Slug Fiend has the ability to shrink anything that it touches to it's own size and then eat it alive. Apparently it has no control of who it shrinks, as Vendetta acidentally touched it and was shrunk. It was unable to eat either Charlotte because of it's speed. By the end of the episode it was eaten by the Giant Kitty, along with the Gianting squid fiends . Charlotte also thinks it's a puppy. It's voiced by Amy Winfrey.