At the beginning of combat on your turn, target creature you control gets +2/+0 until end of turn.
At the end of combat on your turn, if a player was dealt 6 or more combat damage this turn, transform this enchantment, then attach it to a creature you control.

Double Overdrive — Equipped creature gets +2/+0 and has double strike.
Equip (: Attach to target creature you control. Equip only as a sorcery.)