Dogzilla (a parody of Godzilla) is a super villain from Chincinatti. Timmy wanted a villain too powerful for Catman so that he ask for help to the Crimson Chin, then Cosmo thought of Dogzilla and Timmy wished that Cosmo and Wanda created Dogzilla. He was eventually defeated by The Crimson Chin and Catman. His only appearance is in Catman Meets The Crimson Chin.
There is also a book called Dogzilla which is a children's picture book by Dav Pilkey, the author of the Captain Underpants books.