Magic-revealing spells are a popular party trick among students of the School for Gifted Unicorns. Of course, since unicorns generally already know the color of their magic, they're far more interesting when used in mixed-tribe or even mixed-species company. Pegasus (and griffon) magic tends to concentrate around the wings, earth pony magic around the hooves, and unicorn around the head and throat; all tribes' magic concentrates around the cutie mark.

Bonus: unglowy version