Because Regina wore it lol.

Because I'd be able to use it to disguise myself

Pfft disguise I just charge into places as myself and hope for the best.

^ Please, I'd disguise myself as my professors and say there will be NO final exams! You're not thinking big enough, for shame! And you call yourself a villain fan lol!

A true villian can go up to his or her professor with a freeze ray and demand no exams for the year in front of the class, and in the process acquire a small army of minions!

^ Well, then, why don't you do that so you don't have to worry about math ever again? If you could do that, you would've by now, considering your hatred for math lol. Besides, with the 6 Lead Clover of Oz you'd be able to turn yourself into Regina, Azula, and Bellatrix. It would be the ultimate Halloween costume lol. Besides, while the Camelot Spy Necklace is the best looking (though I wouldn't be able to wear it because it's clearly for a woman), I don't want anyone spying on me!

Math can kiss my ass. I totally would have, to bad I don't have a freeze ray. The Zanarchy lent it out to the Katara Kooperation and we never got it back. I'd be Reginazulatrix. Eh they could spy on me they'll basically see me at work all day muttering various curse words so quietly no one can hear them.