Lavaworm

Lavaworms were large worms native to the Sun and to the Elemental Plane of Fire. Highly territorial, they enjoyed eating anything colder than themselves, but required extremely high temperatures in order to reproduce.

Description
Typical lavaworm adults were about 5 ft (1.5 m) in length. They had a somewhat elastic brown or dull red skin and resembled living chunks of magma. Both extremities had a set of eyes and a mouth filled with sharp teeth that resembled needles. Despite appearing symmetric, one of the mouths was slightly smaller than the other. The larger mouth was located at the creature's front and corresponded to the direction it moved.

Behavior
Generally aggressive, lavaworms attacked any moving creature whose body temperature was than theirs. The only cases in which they attacked a similarly hot creature, such as a helian, an efreeti, or even another lavaworm, were with the purpose of laying eggs.

Combat
Capable of moving in fast bursts of speed, lavaworms were experts in surprising their targets. They made ample use of their sharp and extremely hot bites, as well as a breath weapon of sulfurous gas that could temporary blind their victims.

Ecology
After choosing an appropriate host to lay their eggs, lavaworms attached themselves to it and laid about 500 eggs. The high temperature of the host's body allowed the eggs to hatch, after which the larvae rapidly consumed the host's body and everything edible in sight, including each other. This process continued for about one week, after which the surviving young lavaworms spread out in search for more food and territory.

At one year of age, a lavaworm reached maturity, attaining its peak size. It then started its reproductive cycle. Female lavaworms were permanently fertile, but males were fertile for only about one week, during which time they searched for as many females as possible to mate with. After this period, the males became sterile.

In the last stage of a male lavaworm's life, it became extremely territorial and searched to claim for a territory to hunt, which it defended for the rest of its life as it continued to grow. A sterile male could reach a size of up to 30 ft (9.1 m) and its maw could grow as large as 4 ft (1.2 m).