This is an interesting card. For cost 1 you are getting a 4/3, but as an additional cost to play- you have to destroy an ally you control. You can combo this in classic and get some benefits, or you can choose a really cheap cost 1 ally and destroy it to bring out invader on turn 2 and be attacking for 4. A respectable card, even if it's held back a little bit. I'd consider running it in a deck, especially an ally heavy mage or warlock.