Debuting in the title The Incredible Hulk, Zzzax is a humanoid creature formed from electricity by an act of sabotage at a Con Ed nuclear power plant in New York City. A group of terrorists destroying the dynamos started a chain reaction that causes a rapid build in energy, which takes on a life of its own and absorbs the minds of the terrorists and several engineers. By using the electrical energy from their brains, the entity is able to achieve humanoid form and sentience. Calling itself Zzzax, the entity fights the Hulk and Hawkeye before being defeated.
The character returns to the title Hulk and repeats its behavior at a research center in Chicago. The Hulk battles the entity to a standstill before several scientists shut down the process that creates Zzzax. Zzzax reappears in the title Luke Cage, Power Man, and hunts the men responsible for its last defeat. Power Man defeats the entity, but not before it kills one of the scientists Zzzax returns in the title Hulk to confront an intelligent version of the monster (possessing the intelligence of Bruce Banner), but is quickly defeated. Mephisto later reforms the entity in the limited series Secret Wars II, although it is defeated by the Thing. In the title West Coast Avengers the character Zzzax teams with fundamental force villains Graviton; Quantum and Halflife, but is shortcircuited by Hawkeye.
The title Hulk details how Zzzax is eventually captured and contained by S.H.I.E.L.D., who transport it to Gamma Base. General Thunderbolt Ross arranges for his mind to be transferred into Zzzax's body and battles a new version of the Hulk, whose alter-ego is Rick Jones. Ross relinquishes control of the entity soon after saving his daughter Betty Ross Banner, realizing that his actions had risked lives. Zzzax battles Iron Man in the title Marvel Comics Presents and Cable in the self-titled series.
The entity reappears in the title New Avengers and participates in the mass escape by super-villains from holding facility The Raft. The second volume of the title She-Hulk reveals the character has been contained by S.H.I.E.L.D. After briefly escaping and turning the defence systems of the organisation's Helicarrier against its agents (including the Life Model Decoys), it is recaptured by She-Hulk.
The Mighty Avengers later apprehend Zzzax when he attacks New Delhi.
Zzzax later appears in the services of MODOK Superior when it comes to him attacking Red Hulk.
During the Fear Itself storyline, Zzzax was with MODOK Superior when it comes to competing against Zero/One and Black Fog into getting to Red Hulk first