Jörmungand

In Norse mythology, Jörmungand or Jörmungandr was the legendary "Midgard Serpent", a sea serpent which grew so large, that it could encircle the world and grasp its own tail with its mouth. It was the son of Loki and the giantess Angrboða.

Jörmungand appears in the Teenage Mutant Ninja Turtles (1987 TV series) episode Northern Lights Out, but is actually a robotic submarine utilized by Eric the Red-Eye. It attacks the, , and Professor Svenson in their stolen longboat, and they all fear they will be eaten, until realizes it is mechanical when he catches a glimpse of gears inside its mouth. Donatello disrupts the serpent's attack with his bō and they enter it. Svenson reprograms the coordinates for Jörmungand and they head to the volcano where Eric and his vikings are located. The vikings take Jörmungand back over and crash it into some rocks, hoping to stop the Turtles and their comrades. One of Eric's men laments the destruction of the vessel they used to assist in their conquering, but Eric says he is insured and doesn't take its demise to heart.