Sword of Hours (Forgotten Realms Commander 61) - Uncommon Magic: The Gathering Card

Whenever equipped creature attacks, put a +1/+1 counter on it.
Whenever equipped creature deals combat damage, roll a d12. If the result is greater than the damage dealt or the result is 12, double the number of +1/+1 counters on that creature.
Equip (: Attach to target creature you control. Equip only as a sorcery.)