Boom 'er Yang! (and other nonsensical puns)

From the depths of the Everfree, a boomerang which drastically alters the personality of its wielder seeks the ex-villains of Canterlot High

In the spirit of a similar episode from Ed, Edd, n Eddy, a boomerang with mystical properties seeks to twist Canterlot High's most antagonistic personalities into reversed parodies.