He is black and pale gray on the underside. Frank wears a blue swim trunks in the episode "Ripped Pants" and a light olive green and dark green suit, red tie, briefcase, and a small light brown hat with a red stripe in the episode "You Don't Know Sponge."
Role in series
After SpongeBob rips his pants off and realizes the mistakes he made, he asks himself if he's the bigger loser on the beach. Frank pops up from underneath the sand, and reveals that he was buried in the sand and forgotten. He, along with Millie and Dexter, sing the "Ripped Pants" song with SpongeBob. Frank plays the drums during the song. At the end, he and the other band members rip their pants just like SpongeBob.
"You Don't Know Sponge"
When he hears Patrick making whale sounds, he thinks it is his ex-wife, Martha, calling until his friend assures him it is not.
"Mutiny on the Krusty"
He is one of the things in the severe rip current.