Ryze, the Rune Mage

Mage (This creature enters the battlefield with an AP
counter on it. {2}, {t}: This creature deals damage
equal to the number of AP counters on it to target
creature you don't control. Activate this ability only
during a combat phase.)
{2}: Tap target creature, then untap Ryze.
Activate this ability only once each turn.
"A step ahead of cataclysm."