Giant Rodent Skull

My first impression was that this was a vehicle of some sort, but the S.S. Dolphin II claims that it was once a mouse. I can almost see it: the cranial ridge, the extended jawbone...

Yes, now that I think about it more, this is clearly the skull of some enormous rodent. I'm glad I can always rely on the S.S. Dolphin II to steer me right.