Cybernetic bleed-back was a potentially deadly side-effect of biological combining with mechanical or biomechanical contraptions. It was most notable as a side effect of the Hand of Friendship used to pilot the one and only Leviathan-gunship -- Talyn.
If the cybernetic component began to transfer intense, negative emotions or stress to the wearer, these feelings would manifest physically. The wearer's body would begin to form painful lesions on the skin. Unless the cybernetic component was removed, it would kill the wearer. This nearly happened to Bialar Crais, as he was the pilot of Talyn, until John Crichton and Aeryn Sun removed it.
Cybernetic bleed-back appeared in an episode of Farscape.