Shadow Nova

Description
Turn a 2x2 area into Shadow Creep.

Balance Changes
PreAlpha - Added: Shadow Nova 7 mana Deal 1 damage in a 2x2 area, then turn the area to Shadow Creep.

v. 0.0.1 - No longer deals 1 damage before turning the tiles into Shadow Creep.

v 1.71 - Cost reduced to 4 mana.