Had Mercurial, The Supervisor

Whenever one or more -1/-1 counters are put
on a creature you control, you create a 1/1 Goblin Had creature token with wither.

Creatures you control with -1/-1 counters on them have wither.

{t}: Put a -1/-1 counter on target creature.

{u}{u}: Untap Had Mercurial.