Like all double-faced cards, werewolves start out on their front side. No matter what kind of werewolf we’re talking about, they all have one thing in common: if no player cast a spell on the previous turn, they transform to their back side. The werewolf will know if spells were cast before it enters the battlefield, so in most circumstances, you won’t be transforming the werewolf the turn after you play it (since you likely cast the werewolf itself). For instance, let’s take a look at Convicted Killer. The Killer starts out as just a 2/2 for three mana – pretty basic. But if we manage to go through a turn where no one (including your opponent) casts a spell, the Killer’s ability will trigger during the next upkeep, and that next upkeep, the Killer transforms into a 4/4 Branded Howler – much bigger.
But like all good things, they have to come to an end. The other common link with the double-faced werewolves is that once they’re on their back side, if a player cast two or more spells on the previous turn, they’ll transform back to their front side. Note that the same player has to cast two or more spells for the ability to trigger – one player casting a spell, and the other player casting a spell isn’t enough, since the same player didn’t cast both spells. For instance, if you have the Branded Howler on the battlefield, but your opponent managed to cast two spells last turn, the Howler’s ability is going to trigger and it’s going to shrink back into the Convicted Killer.
Today’s Rules Tip written by Nathan Long