This is a chump blocker that makes your opponent reconsider attacking you. If they swing into this, you'll be able to swing back the next turn with a 3/3 flyer. It also works in a sack deck since it'll give you both the benefit of the sack outlet as well as a bigger creature. The downside to this card is that it costs 3. Honestly, I think would do a lot better as a double-white creature since it does need to die in order to get the most out of it, which either requires another card on your end or an opponent with a creature to attack you (always a dangerous situation due to combat tricks). It's alright, but not superb.
Pros: Chump blocker that turns into an attacker
Cons: 0/3 for 3, requires death, defender