databank
900 year diary
nucleus of the swarm
A malignant life-form from the microverse that moved from host mind to host mind, attempting to escape into the macroverse, or real world. Eventually it found its way into the Doctor's brain and was removed and enlarged until it could successfully exist in the macroverse. After making slaves of the personnel at the Bi-Al Foundation, it was transferred to a base on Titan. There, huge tanks had been prepared for its Swarm, but the Doctor and Leela destroyed them. Trapped in the middle of the tanks, the Nucleus was obliterated.