Sunworm

"I recently came upon an account of Praag after Magnus and his forces liberated the city. It seems that festering in the carcasses of the Chaos Trolls, there were unusually large maggots. A soldier tried to skewer one on his sword only to be jolted by its foul energy. Thereafter, they were instructed to burn the dead."

—Reinholt Schent, Scholar of the Fantastic

The Sunworm is a mutated maggot grown fat and oily with the power of Chaos. Unlike their natural kin, these creatures lack mouths and feed by rubbing their bodies against their meals and excreting their wastes through their pale, segmented hides. Strangely, these creatures supplement their diet by devouring sunlight. During the day, their undulating bodies writhe in the delicious energy cast by the sun. As a result of this light, they build up a charge of energy that allows them to survive through the dark hours. This energy can also be used defensively. If a creature comes within a yard of a Sunworm, the creature reflexively releases a jolt of powerful energy. Sunworms can grow as large as six feet in length.

Sunworms are blessedly rare, contained to the deserts of Khemri and the Chaos Wastes. The Empire’s climate does not lend itself to these foul creatures. Still, some cultists use these creatures to eliminate rivals or particularly troublesome Witch Hunters.

Source

 * Warhammer Fantasy RPG 2nd ED -- Tome of Corruption (pg. 121).