This is like a delayed removal to kill a big minion or taunt and it either baits an aoe or kiss your minion bye. A better patient assassian. Warriors can run it with the 1 mana charge and hunters with their tundra rhino.
Bold prediction, not only is this gonna be auto-include in certain decks (especially druid), it's gonna be essential in countering a (very likely) quick quest meta. Dropping this on turn 4-5 before they get to play their reward is gonna completely mess up their curve and give you more time to stabilize.
I have no idea if this will end up seeing constructed play, but I just kinda like it as a card. It's a really neat design IMO, nothing special but I can't help but see myself using it in a few control decks, even if it just ends up being a boring 2 drop/pseudo-removal half the time.