i keep a few rotating 'why not?' slots open in my rat deck(read: pack rat deck) for cards just like this one. i could see it being a fun card to hit the table later on in multi-player, and if the mana isn't there, an easy choice for discard to make more pack rats. you want an awesome combo? pay three or four life, and let the pack rats enjoy the boost. or marrow-gnawer. or let your opponents cash in and then drop a pestilence rats. this one won't necessarily win you the game, but it'll make getting there fun, and that's why you're playing in the first place.