Baby Marvin is a minor character from the show. He is a toddler version of Marvin the Martian. In War of the Weirds, he pays a visit to the babies, but no one likes him so Baby Taz befriends Baby Marvin to make him feel welcome.
- War of the Weirds was the only episode to feature Baby Marvin. The other ones were songs.
- He is another character to never be seen wearing a diaper.
Minor: Baby Pepe • Baby Marvin • Puppy K-9 • Baby Elmer • Baby Foghorn • Puppy Barnyard • Baby Porky • Baby Wile E. • Baby Road Runner • Baby Gossamer • Baby Duck Dodgers • Baby Instant Martians • Baby Michigan • Puppy Marc Antony • Baby Sam