(Definition) Similar to a helper monkey who would assist those who are physically disabled. However, in this case the monkeys purpose is to fetch snacks or beers for those who are too lazy to get up.
Originates from a 2003 garage football party. The name may have died but the fact that said individual referred to as "Snack Monkey" hated the nickname, has ensured that it has remained popular
When a group of friends all get up at the same time to get snacks. Usually the group walks in single file to obtain the snacks. If the the snack station is lacking then the snack train derails.
friend 1 "Anybody wanna getsnacks?"
friend 2 "Snacks buddy?"
friend 1 "All aboard the snack train!"