Finally coloured this!
Seems like the big blue has magnified in size to the titanic state he is at now, large enough to snap at passing aircraft at cruising altitude if he were to rear back. So heavy he has become, that he's wreaked havoc on the terrain beneath him and that gut, enough that lava has appeared.
Currently seems like he's taking a rest from eating many, many tons of "food" and cities... He shall be bigger soon.
Original sketch/Linework by the amazing draconder http://www.furaffinity.net/view/17793417/
Additions, character, and colouring by myself
EDIT: Moar Lava! May be getting a bit too heavy... nah...