Milton Fine & Vril Dox(Modern Age DC, Brainiac)

Milton Moses Fine was a mentalist who performed under the name "The Amazing Brainiac". Fine's telepathy attracted an alien entity which believed itself to be the disembodied mind of a Coluan scientist named Vril Dox. The entity possessed Fine's body, and he was tranformed into a villain calling himself Brainiac. It would later be revealed that the entity was a cloud of nanites created by the true Vril Dox, programmed with his memories.