The Clockworks

{t}: Roll a d20 if the result is 1-4 then exile
target creature. If the result is 5-8 then destroy
target creature and add {2} to your mana pool. If
the result is 9-12 nothing happens. If the result is
13-16 add a +1/+1 counter to target creature. If
the result is 17-20 than target non-creature
non-land permanent becomes a creature
with power and toughness that are equal to
it's converted mana cost.