Thor, Resurrected

More Than Meets the Eye {2}{u}{r}{w} ( You may
cast this card converted for {2}{u}{r}{w}.)
At the beginning of each end step, bolster 1.
(chose a creature with the least toughness among
creatures you control and put a +1/+1 counter on it)
When Thor dies, return it to the
battlefield converted under it's owners
control.