Grim Poppet enters the battlefield with three -1/-1 counters on it.
Remove a -1/-1 counter from Grim Poppet: Put a -1/-1 counter on another target creature.
The second ability can target any creature except the Grim Poppet whose ability is being activated. It can target a different Grim Poppet. It can be activated multiple times targeting the same creature.