Lion's Paw Sanctum

Lion's Paw Sanctum enters the battlefield tapped.
{t}: Add {w} or {b} to your mana pool.
{3}{w}{b}: Lion's Paw Sanctum becomes a 4/2 white and black Elemental creature with first strike and deathtouch until end of turn. It's still
a land.

The lion's strike is both quick and deadly.