Fifty Foot Croc Feeding on Blue Whales?

Neeto.

http://www.huffingtonpost.com/2011/07/16/giant-sea-monster-skull-displayed_n_899903.html#s309750

I think the animal predated whales.

What do you think it ate with those huge jaws?

Here we go:

http://en.wikipedia.org/wiki/Pliosaur

Their prey may have included fish, ichthyosaurs and other plesiosaurs