Someone who uses the phrase "Lol" too often, and/or doesn't really laugh.
Poodle132: I went to the store yesterday and I fell.
Narwal6: LOLOLOLOLOLOLOlOLOLOLOLOLoOLOLoLOoLoLOLOL
Poodle132: It wasn't really that funny.
Narwal6: LOL
Poodle132: You Lol Monster.