Marvin appears to be a much more primitive species of plankton. Marvin is notably smaller than some of Sheldon's other cousins.
Cousin Marvin appears when Plankton is explaining how his species are the most important living creatures on the planet. He uses cousin Marvin, who he describes as stupid, as an example, but he then explains how Marvin has planktonic plant brains that make up half of the Earth's oxygen.
|Plankton (V • E)|
Sheldon J. Plankton • Clem • Rufus • Rainchild • Gordon Plankton • Lily Plankton • Basia • Alvin • Silas Plankton • Planktonamor • Dead Eye Plankton • Grand Dad Plankton • Green PlanKrab • Ideal Plankton • Cousin Marvin • Dream Lily Plankton • Mama Plankton • Moe Bros • PlanKrab • Plankton zombies • Planktonamor • Red PlanKrab • Seymour • Sheldon J. Plankton (Bikini Bottom 2)
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