Entomb: Play a 7/7 Steelbound Dragon with Flying and Overwhelm
Entomb - The ability of a unit with Entomb will activate when it dies. This combines well with effects that sacrifice units as a cost.
Flying - Flying units can only be blocked by other flying units, but can block ground units normally. They can also be directly attacked by Killer units and Relic Weapons.
Overwhelm - A unit or spell with Overwhelm will deal any excess damage to your opponent on your turn (does not work while blocking).