Encephalon Gemmule

Due to the influence of the Far Realm, the eggs within an encephalon cluster no longer hatch into illithid tadpoles. Instead, when one of an encephalon cluster's eggs reaches maturity, it is ejected from the mass as an encephalon gemmule.

When spawned, a gemmule appears as a misshapen, spindly legged, pyramid-shaped nugget of soft, fleshy matter. If left to its own devices, an encephalon gemmule grows into an encephalon cluster in a matter of days, at which point it begins producing its own gemmules.

Encephalons

When an illithid colony lays its eggs dangerously close to a Far Realm rift, an egg sac has a chance to mutate into what is known as an encephalon cluster—a ravenous, slimy, psionic, brain-shaped mass that spawns horrors called encephalon gemmules.