Prospero, Poiteinian Marshal

Vigilance (Attacking doesn't cause it to tap.)
Whenever Prospero, Poiteinian Marshal blocks
or becomes blocked, put a +1/+1 counter on it.
When Prospero, Poiteinian Marshal dies, choose one:
• Put a +1/+1 counter on target Human you control.
• Put a –1/–1 counter on target Human an opponent controls.