Marimo is a green globe-shaped algae that grows in Japan as well as Iceland and Estonia.
Its name comes from 'mari' which means bouncy ball and 'mo' which means any water plant. Marimo is a threatened species and is currently protected in Japan.
Some Japanese keep marimo as a pet and folklore dictates that good luck comes to those who look after their marimo well.
Marimokkori is a Japanese character who is a marimo. His name is a play on words, 'mokkori' being slang for a man's crotch. Marimokkori is therefore quite well equipped.