Rex is a bloodhound belonging to Freidrich and agent with D.O.G.S., who appears in Cats & Dogs: The Revenge of Kitty Galore.
In the trailer, he caught Kitty Galore in her puppy disguise. He then went over to his dog bowl, and pressed his name, contacting Dog HQ. He told an agent that he just spotted Kitty Galore.
The voice of Rex is currently unknown.
- Rex might be confused with Buddy sometimes.