While slow, the ability to tutor and cast instants at any time by unattaching it has earned it a slot in many a Boros deck
Toxrill, the Corrosive Sliding into this spot is Toxrill, the Corrosive, a 7/7 slug horror ( ew ) that gives -1/-1 counters to creatures you dont control on your end step
The idea of copying opponent's creatures is somewhat interesting, but it places you at the mercy of what the opponent has for you to take any value out of this
Loyalty counters, +1/+1 counters, charge counters all of it
It draws two cards whenever it gets into combat, but the key lies in surrounding it with many cards that trigger all the timethink Soul Warden, Inventors' Fair, and so on