Kroll

Kroll is a unique creature which originated as a giant squid from Earth, transported to one of the moons of Delta Magna by Human colonists. After swallowing a segment of the Key to Time, the squid was mutated into a colossal man-eating monster which remained alive for centuries. Kroll henceforth became the central figure in the religion of the relocated Swampies, who offered living sacrifices to their paludicolous deity.

Biology
Kroll is a massive creature. The central mass of its body measures a quarter of a mile in diameter (402.336 m), which, combined with its 600-yards tentacles (548.64 m), results in a complete armspan of almost a mile. It is estimated to have as many as 60 tentacles, used to capture prey, which it locates by surface vibrations. Although Kroll's diet is omnivorous, and the Doctor claims that it is primarily a vegetarian, it won't hesitate to attack prey that comes too close to it. Additionally, it can remain dormant beneath the mud for centuries and still capture prey with its tentacles to feed itself even while asleep. Its metabolism produces vast quantities of methane.

Appearances

 * Doctor Who, season 16, "The Power of Kroll" (1978)