|Species||Unique species of Pliosaur|
|Place of origin||Inadvertently thawed out during glacial meltdown|
|Age||Millions of years old at time of his demise|
|Affiliation||Partnered with Cretaceous|
|Behind the Scenes|
|Created by||Carlos Saldanha|
|Performed by||Mixture of whale and tiger sounds|
Maelstrom is a member of an unknown species of Pliosaur. He was released from his icy prison alongside his partner, Cretaceous, during the Wisconsin Stage glacial meltoff around 13,300 years ago.
Frozen long ago with Cretaceous during the era of the dinosaurs, Maelstrom was imprisoned in a great block of ice that was jarred loose when the wall of ice that it had been part of began crumbling, due to global warming loosening it. The ice melted, releasing both Cretaceous and Maelstrom into the lake which was all but abandoned by most animals. When they made it to the ice lake, the first animal that they had encountered and eaten was Stu the glyptodon, leaving behind only his shell. The two sea reptiles then swam further down the series of rivers where they eventually reached Manny's herd as well as Crash, Eddie, and Ellie. Maelstrom intended to eat Sid but could not catch him, as Sid was already escaping with Diego, and had only just escaped Maelstrom as he broke off a massive chunk of ice where the sloth and the saber-tooth tiger had stood only moments before.
Later, when the dam broke, the two reptiles went swimming on the wall of water that was slowly approaching the escaping masses and pulled down Manny when he was swimming to save Ellie. Manny devised a plan to rid himself of the two sea reptiles, by having them try to chase him, he tricked them into hitting a log that was wedged under a large rock. The plan worked, freeing Ellie, and knocking the two reptiles down with the boulder.
Maelstrom, like Cretaceous, was incapable of speech and so communicated in loud growls or roars. Maelstrom was a large pliosaur, thickly built with a large mouth filled with sharp teeth ideal for breaking bone, faintly glowing yellow eyes and armour-like teal scales that were topped off with spikes and bumps, propelled through the icy waters with large, flat fins. Within Maelstrom's digestive tract were several parasites: a number of stunted giant single-celled organisms and a large parasite with multiple eyes and a beak.
If one is to assume all accounts of the fates of Maelstrom and Cretaceous are true, then the duo were likely mortally wounded after Manny tricked them to get stuck under a log and then subsequently crushed under a falling boulder. Eyed at this point by vultures, this left them to be sucked out of the area along with the waters through a giant crack in the ice wall, apparently dying in the process or soon afterwards when they were beached. Their dead bodies were then discovered by mini-sloths, which carried them away to feed on. They were said to make "good sushi".
- True pliosaurs had longer necks than is shown in Ice Age: The Meltdown, along with a longer crocodilian snout and no plates or scutes on their hides.