A Mortron is an alien creature that is actually two creatures in one, a yellow with black spots bottom half with four wheels, and a dark red top half which appears to be an elongated, sharp head until the creature separates revealing it has wings. These two parts can seperate, move fast on the ground, and attack in unison from above with sharp beaks. They are also regenerative, if one Mortron is cut in half, two new ones are formed out of the two pieces. They come from a world that was later destroyed when its sun went nova.
- The Andalite Chronicles - Visser Thirty-two, who will later become Visser Three, has two Mortrons as pets, Jarex and Larex. He sets them to attack Elfangor and Loren. When Elfangor uses his tail blade to slice the two Mortrons in half, they regenerate to become four Mortrons. He escapes them by running away faster. Later, he and Loren destroy them.