Revealing mistake: When one of the men picks up Garfield from his cage to display to potential buyers at the pound, you can see the man's right hand "entangled" with the computer-generated Garfield.
Garfield: The Movie (2004)
Plot summary
Directed by: Peter Hewitt
Starring: Bill Murray, Jennifer Love Hewitt, Breckin Meyer, Stephen Tobolowsky
Garfield, a fat, happy, lazy cat, is enjoying the good life with his owner Jon, until one day Jon adopts a dog named Odie. Garfield is having trouble getting along with Odie until Odie goes missing. While Jon and vet Liz go looking for Odie, Garfield forms his own plan to save the dog from TV star Happy Chapman.
Matt
More mistakes in Garfield: The MovieMore quotes from Garfield: The Movie
Trivia: Bill Murray agreed to be in the film without reading the full script upon seeing the name "Joel Cohen" listed as a writer. It turns out he thought he was signing onto a film co-written by "Joel Coen" of the Coen Brothers fame. It wasn't until he began recording his lines sometime later that he realised his mistake.
Answer: The song is called "Holla", by the Baha Men (of "Who let the dogs out" fame).