Burning Skeleton

Whenever Burning Skeleton enters the battlefield,
put three +1/+1 counters on it.
Whenever Burning Skeleton deals combat damage
to target opponent or a creature that opponent controls, that opponent may pay {u}{u}. If they do, remove three +1/+1 counters from Burning
Skeleton.
A powerful enemy, but its power lies in the fire.
- Donna, Verdant Creator