When a group of males or females looks hot, just from being in close proximity to each other. However, if you were to scrutinize each one individually you would see that they are either simply average looking or even repulsive. This is from the television show "How I met your mother" and is explained by Barney (Neil Patrick Harris)
AKA Bridesmaid Paradox, Spice Girls Conspiracy
Person 1: Dayum gurrl, check out that soccer team! Those boys are cute!
Person 2: Not really, if you were to look at each one individually you'd see that they are actually quite unattractive.
Person 1: OMG, you're actually SO right. Freaky shit!
Person 2: I know, it's called the Chearleader Effect, but is also known as the Bridesmaid Paradox or the Spice Girls Conspiracy.