To determine the total cost of a spell, start with the mana cost or alternative cost you're paying, add any cost increases (such as that of God-Pharaoh's Statue's first ability), then apply any cost reductions. The mana value of the spell remains unchanged, no matter what the total cost to cast it was.

In a Two-Headed Giant game, the last ability of God-Pharaoh's Statue causes the opposing team to lose 2 life.