A military helicopter drops experimental sonar transmitters into the water, causing a pod of whales to go out of control and start ramming a nearby glacier. In the chaos, the helicopter crashes into the glacier, and the combined damage breaks the glacier open, thawing two hibernating, prehistoric creatures.

A drilling platform off the coast of Japan is attacked by the Giant Octopus, which has tentacles large enough to wrap around the entire structure.

MacNeil investigates the corpse of a beached whale covered with bloody wounds, she extracts what appears to be a sharks tooth from one of the wounds.

Mega Shark leaps tens of thousands of feet into the air from the ocean and attacks a commercial aircraft, forcing it to crash into the water.

A U.S. "naval destroyer" engages the megalodon, but is destroyed after its guns fail to destroy the Mega Shark.

Mega Shark destroys another destroyer sent by Baxter.

Mega Shark resurfaces and bites off a large portion of the Golden Gate Bridge, killing thousands of civilians.

Mega Shark and the Giant Octopus begin to fight, but they separate and the shark attacks the submarine, dragging it in its mouth killing the rest of the crew.