Moonmist

The Fog that picks a side. A green damage-prevention spell that exempts two creature types is a small idea with a sharp edge: this one stops all combat damage except what Werewolves and Wolves deal, and bolts a mass transformation onto the front of it. The transformation is the part doing the quiet work. The werewolf shell's central anxiety is that any spell cast flips the pack back to their weaker human fronts; here the spell is the one casting, flipping every Human (your dorks, sure, but the point is your own werewolf fronts) to their stronger backsides at instant speed, on your turn, in the middle of combat. With wolves on the board, the prevention clause becomes a one-sided wall: your transformed beasts deal and survive while every other creature in combat hits nothing. Defensively, your freshly flipped wolves block attackers and kill them without taking a scratch. Offensively, your pack swings and connects, your opponent's blockers eat the swing but their own damage back gets prevented, so trades become free. The card is not unconditional, but it is not finicky about it either: cast it with no Werewolves or Wolves in play and it is simply a two-mana Fog, which is a fine floor and a poor reason to maindeck it. The transformation rider is what turns a symmetric prevention effect into a tribal reward worth building toward.