labyrinthodont, an extinct amphibian from the Land that Time Forgot. Something about the critter's hungry, beady little eyes lit up my brain. Maybe it's the ladykiller smile? I'm considering replacing all the crocodiles in my setting with these things, at least in And. As cool as these things are, it's the teeth that clinched me using them in some way.
This is a cross section of one of those pearly whites. That's where they get their name! Dead language lesson! Huzzah! This begs to be reworked and used as a dungeon. Very Planescape Caverns of Thought, Ilsensine the God-brain sitting there in the middle with his neuron bundles stretching out into the cosmos. It needs some simplifying to slow down the inevitable player revolt and DM stoning, but it's too cool not to use.