Thank you Brian Switek for entering the phrase “bone-burrowing snotworm” into my nightmare lexicon. 
Today Brian wrote a lovely article on icthyosaur falls, which are like whale falls but, you know, they happened a long time ago to, you know, icthyosaurs.
The point being that ichthyosaur carcasses, like whale carcasses today, could serve to feed an entire ecosystem of bottom-dwelling, presumably nasty, critters. Sayeth Switek:
How different organisms utilized marine reptiles depended on the state of the carcass. When the dead marine reptiles were still covered in flesh, sharks and cephalopods probably picked at the body. Once denuded of soft parts, though, the reptile’s skeleton could have been a refuge for various encrusting and burrowing organisms (although, as far as I am aware, no one has yet found evidence of bone-burrowing snotworms among Mesozoic marine reptile skeletons). Fine-scale field investigations are required to further investigate this hypothesis, but Hogler made a reasonable case that marine reptile deadfalls may have been ecologic precursors to modern whalefalls. Perhaps some of the organisms which congregate to dismantle whales today are the descendants and relatives of creatures which used to greet the carcasses of mosasaurs, ichthyosaurs, and other Mesozoic sea dragons.
So thusly we are reminded of a past, reason not to go into the water: bone-eating dominatrix tube worms with a dwarf fetish.
Ah, love. In all its filthy disgusting forms.