Munchie is one of Homer's hippie friends. He is a co-owner of the Groovy Grove Juice Corporation (along with Seth) and was a friend of Mona Simpson in the 1960s.
Between Seth and Munchie, Munchie is the more laid-back of the two, and also more spontaneous, as he was the first one to go along with Homer's idea to go to town to freak out squares.
When Mona Simpson died, he and Seth were present at the funeral home, with noticeably grayer hair.
He and Seth also attended Lisa's town meeting about Lake Springfield.
 Behind the Laughter
Munchie's name is a reference to the hunger side-effect of Cannabis ingestion, which results in trying to eat a lot in an attempt to quell its addictive properties.