That's One Big-Mouthed Pliosaur

"Predator X was the most fearsome animal ever to swim the oceans"
telegraph.co.uk (March 17, 2009)

"A marine monster described as the most fearsome animal ever to swim in the oceans boasted a bite up to 11 times as strong as that of Tyrannosaurus rex.

"The fossil remains of the huge pliosaur were dug up last summer from the permafrost on Svalbard, a Norwegian island close to the North Pole...."

The tone of the article is a bit breathless, and I've read about several 'the most fearsomes' over the decades, but: yes, this "Predator X" does seem to have been fifty feet of big-toothed, seriously dangerous, marine carnivore. With jaws about ten feed long. That's what the article said, anyway.

Not the sort of thing you'd want near a swimming beach.

I may have missed it, but I didn't catch how long ago this big biter lived. Presumably, it's extinct by now. Like the coelacanth.