All combat damage? Ever? I think you mean until end of turn. Also, compare to Haze Frog: this costs 1 less but has +2 toughness. The only thing better about Haze Frog is that it also lets you Shock an attacker. I think either but not both benefits would be good.

I wasn't aware of Haze Frog. I think with green's current trend of having very efficiently costed creatures that neither the CMC needs to increased or its toughness decreased. Additionally, Haze Frog is a common and this is an uncommon which allows it to be a little bit better.

If I remember correctly, I read an article where Haze Frog was discussed. Design costed it more efficiently, but development bumped the cost up significantly because it was too good to have Fog attached to a body.

I have a EDH spiritcraft deck. And let me tell you, returning Kami of False Hope to the battlefield from the graveyard every turn can shut down whole multiplayer games. I assume they were afraid of effecient Haze Frog, plus repeatable bounce... but I don't know what they were using for that effect.