When something someone does or says is so grimey, but so funny at the same time.
"Pedro just pissed on his girl while she was passed out. You had to be there, it was grimetastic."
1. When a man ejaculates in someones face
"Yo man I just gave Pedro a face full of celebration while he was sleeping, it was grimetastic..you had to be there."
A term used to describe an individual who acts grimey and may perform grimey acts on an object or indivudual.
Pedro just stole fifty bucks from his grandma to buy some drugs! Can you beleive that? He's such a grime reaper.