There was only one way to go for a monster prompt for me: Frankenstein! (Technically, Frankenstein's monster, who was nameless. Frankenstein is the doctor.)
I started with Sinful Colors Exotic Green, then used a dotting tool along with Sinful Colors Black on Black and Revlon Spirit to create the hair and faces.
This guy (in the middle) is my favorite. I'm not quite sure why. Maybe becauses he doesn't have that "Derp" expression that pinkie dude has :)
Be sure to check out the rest of the awesome monster manis in the InLinkz below :)