This is Predator X, a type of short-necked plesiosaur, a pliosaur, exactly the biggest pliosaur with its 15 metres long and 45 tonnes.
It was discovered in Svalbard, a remote Norwegian Arctic archipelago in 2006. Predator X was the most powerful marine reptile ever discovered. Predator X had a head twice the size of Tyrannosaurus rex, its bite force was four times as much as T-rex’s, around 15,000 kilograms over the whole jaw (this could have crushed a 4 wheel drive car with its over 30 centimetre long teeth). And its four flippers could make it speed through the water at five metres a second.
Eventually the mosasaurs took over the Pliosaur place in prehistoric seas.