Ocarina of Time

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 {2} ({2}: Attach to target creature you
control. Equip only as a sorcery.)