I think the cost being

would make more sense and would help balance the card with Otyugh. Right now I feel like this is superior to Otyugh in many ways, not the least of which is the fact that

has in-element Plate/Heavy Armor to make devouring easier. The poison adaption bypasses one of Otyugh's biggest weaknesses (in my opinion). By changing the skill to consume

would strengthen the already strong bond between

and

. If the 7

cost and

devour are going to remain then I think, like others have said, the attack should be reduced to 0.
What if Devour didn't give the stat boost?
I like this idea, it would balance out the already higher Atk|HP and still allow it to get...hungrier? through Plate or Heavy Armor.