R-63 MK-4, The Changing

Changeling
{t}: Add {Y}, where Y is R-63 MK-4's power.
{Z}: put a +1/+1 counter on R-63 MK-4, where Z is R-63 MK-4's toughness.
If a +1/+1 counter would be put on R-63 MK-4 from a source other than itself remove one instead.