The opposite of the women's cheerleader effect (women look more attractive in groups, although unattractive individually) when applied to men. Men who may be attractive on their own will look like a complete douchebag when assembled. Each male's level of toolness is generally acceptable alone but is amplified when mixed with others.
Cody- Dude, Jake and his friends are tools.
Tim- Nah, that's just the reverse cheerleader effect.
Cody- No seriously, he's a tool.
Tim- You're right... it's just worse now.
When one mediocre/ugly girl is surrounded by several ugly girls and looks more attractive then she is. Because of her surroundings she will be perceived to be more hot then she would be if looked apart.
Al: Dude that blond in the project meeting was really hot. I would like to have a late meeting alone with her on a Friday night.
Mike: Al, you are an idiot and a clusterfuck. She is butt ugly, you are just blinded by the reverse cheerleader effect. Because she is surrounded by ugly girls you think she is hot.