Zohtt
From superman.nu: Supermanica
Zohtt
A microscopic intelligence that lives by occupying the bloodstream of unwilling host bodies.
After being drawn to the future, Superman becomes infected by the micro-organism and even after blood tranfusions, it's left to the Man of Tomorrow to trick the alien invader into transfering its life force into the synthetic heart of a Superman replica and becoming trapped (Act No. 403, Aug 1971: "Attack of the Micro-Murderer!").