The Mane-iac

That giant mass of hair must have strangled her brain for her to think a cure for baldness is a city-killing WMD. The best she could hope for would be to rob the barbers after they get rich giving everyone hit by that thing haircuts because the would probably look like Rarity under the effect of poison joke at worst.

What it did to her when she was hit was probably because her hair was already prehensile and messed up her control over it.