Purified Onsen

Hexproof
Whenever you cast a creature spell, you may exile that creature instead of having it enter the battlefield.
{g}:Target creature gets +X/+0 until EOT, where x is the total power among creatures exiled with -.
{w}: Target creature gets +0/+X until EOT, where x is the total toughness among creatures exiled with -.
{r}: Deal X damage to any target, where x is the number of creatures exiled with -.