Elasmosaurus is a member of the plesiosaur family of prehistoric aquatic reptiles; they are not properly dinosaurs, but are included here as they were contemporaries. Plesiosaurs have flat bodies, short tails, and long necks; where a quadrupedal animal would have legs, they have flippers. As they are reptiles, they cannot breathe underwater, though they can hold their breath for an extended period. They are aggressive carnivores, subsisting on fish and small non-aquatic animals, which will be pulled below the surface and drowned. On any successful hit, an elasmosaur has established a hold on the victim, who will then be pulled into and under the water unless they can make a successful save vs. Death Ray to break free. An elasmosaur is not strong enough to thus move any creature weighing more than 300 pounds.