Pewter Mind

At the beginning of each endstep you may
remove a -1/-1 counter from a creature you control.

Put a metal counter on Pewter Mind: Put a -1/-1 counter on each of your creatures. Activate only
once each turn.

{t}, Remove X metal counters from Pewter Mind:
Remove all -1/-1 counters from creatures you control. Creatures you control get +X/+X and trample until end of turn.