This beastie has been going through my head for a while now, but I definitely think the Hideous Zippleback's cooperative breath system in How to Train Your Dragon
sparked the idea (no pun intended
The Hedrin (tentative name) is a creature with three heads that each serve a different function.
--The leftmost head is the powerhouse (the one in the top right corner), bearing the senses of Taste and Smell. Not needing the neural capacity for any other sense, it's smell is incredibly keen, and it's muscle power unmatched. It could easily crush stone in its teeth and penetrate steel armor.
--The rightmost head is the sentinel (the one in the lower left), bearing the senses of Hearing and Touch. It is the quickest and hardest to strike, responsible for the entire creature's sense of balance. It can hear a mouse's breath and sense the air disturbed by a gnat's wings a hundred yards away. It is also rumored to be able to sense the weather.
--The center head is the mastermind, bearing the sense of Sight and the blessing of Sentience. It commands the movement of the body, able to override the independent functioning of the two other heads and move in unison. If you cut off (or smash or impale or generally mess up) this head, the beast dies. It's intelligence is much higher than the average human's, and it can use the mouthed head to speak. Most Hedrin are solitary and fiercely protective of their homeland, but others enjoy the occasional company of humans, engaging in stimulating conversation and offering valuable insight into the world's troubles. Others enjoy an intellectual challenge, and subject the unwary traveller to a game of riddles--one that the traveller rarely escapes alive.
I still have no idea to what universe the Hedrin belongs. I'll probably integrate him into a story eventually. I plan on trying to model him in zBrush (if I ever get the time...-_-). As always, the concept and artwork is (c) to me. I have a picture of its body here [link]