When Grass-Necropolis enters the battlefield, sacrifice it unless you pay .
: Add or to your mana pool.
: Grass-Necropolis becomes a 1/1 red and green Squirrel creature with first strike until end of turn. It's still a land.
.
: Add or 
to your mana pool.
: Grass-Necropolis becomes a 1/1 red and green Squirrel creature with first strike until end of turn. It's still a land.
