BIOGRAPHY page 2
Mentallo's next outing had him join forces with A.I.M. He once again was able to augment his powers using outside technology, also working through ten psychics culled from the group hivemind of Zenith City. With these unwilling batteries, Mentallo dramatically increased his powers and was able to hold off Captain America when the Star-Spangled Avenger breached the A.I.M. cell. Mentallo attempted to seize control over the minds of everybody on Earth, only to face surprisingly resistance from Tony Stark, who employed mental circuitry to shield himself from just such an attack. Instead, Stark was drawn into the cyberastral realm Mentallo now occupied. 
Mentallo probed the invader and learned his secret identity as Iron Man while the two did battle in the virtual realm. This distracted him long enough for Stark to defeat Mentallo, momentarily taking his place at the center of the psychic web. Iron Man used the opportunity to wipe the knowledge of his secret identity from all those on the planet who had learned it over the years, and Mentallo was left in a vegetative state for S.H.I.E.L.D. and Captain America to apprehend. [Iron Man & Captain America Annual '98]
Flumm was incarcerated at Seagate in Georgia, one of a series of penitentiaries set up to hold 
superhuman inmates after the Vault went belly-up. Held in a stasis tank to prevent him from consciously using his powers, Mentallo was nevertheless able to exert himself through the support of Justin Hammer. The criminal financier compensated Mentallo for using him as a medium to telepathically communicate with several criminal associates inside. Hammer attempted to recruit M.A.C.H.-1, his former employee turned heroic Thunderbolt, but Jenkins ended up stopping a riot rather than helping Hammer. [Thunderbolts (1st series) #26]
Several months later, Justin Hammer was dead and Mentallo was in a position to capitalize on knowledge he secretly retrieved from Hammer's mind while they were in contact. He mentally reached out to another Thunderbolt, the former Avenger Hawkeye who was imprisoned as part of a deal getting pardons for his team. Surrounded by people he helped put away, Hawkeye would never survive in prison for long. Mentallo telepathically offered to run interference for Hawkeye, giving him "protection," in exchange for his help escaping. Having few options, Hawkeye agreed. [Thunderbolts: Life Sentences]
Through some telepathic prodding, Mentallo arranged for Hawkeye and a specific crop of inmates to be transferred to Riker's Island: Plant-Man, Cottonmouth and the telepathic Headlok, whom Mentallo used as a receptacle for his own consciousness. Their escape effort proved far easier 
than expected when the Omega-class threat Graviton caused worldwide devastation, including crashing their transport van. The guards were killed in the crash and the inmates broke free. However, the four were still trapped together as a "chain gang," thanks to the security manacles which prevented them from making aggressive actions or getting more than fifteen yards away from one another. They made it to one of Hammer's facilities and prepared to capitalize on the knowledge Mentallo pulled from Hammer's head. However, Cyclone of the Masters of Evil intervened, seeking Hammer's weapon as well, stealing the data files that would have complimented what Flumm already knew. Hawkeye was revealed to be a plant for S.H.I.E.L.D., and Mentallo was taken into custody, sending Headlok's body back to prison with Mentallo's mind inside. [Thunderbolts (1st series) #53-63]
Mentallo was one of numerous tech-themed villains and mercenaries hired by Lucia von Bardas to seek revenge on Nick Fury. Outfitted with additional armor and armaments, they were unleashed on an assembly of heroes in New York City. Von Bardas had weaponized the villains' armor, however, turning them into components of a massive bomb when her plans reached their apex. Mentallo and most of the tech-villains were beaten and collected by the authorities in the aftermath of the battle. [Secret War #3-5] Flumm was imprisoned on the Raft, but he was among a large group of villains who were freed from their cells when Electro attacked the Raft on behalf of Hydra. Mentallo escaped the island prison during the riot that followed. [New Avengers (1st series) #1]
Tired of getting beaten up by super-heroes, Flumm decided to try low stakes larceny with some high stakes poker at the casinos in Reno. Being a mind-reader made cleaning up at the tables easy, but Mentallo suffered ridiculous bad luck as the Purple Man had taken over that very same casino days earlier. Chased out of town, Mentallo responded to a psychic summons from A.I.M.'s 
former Scientist Supreme, M.O.D.O.K. At a Brooklyn warehouse, M.O.D.O.K. schooled his crew of new minions on his plan to steal a Hypernova from the alien Infinicide. As the only other psychic in the bunch, Mentallo recognized that M.O.D.O.K.'s money was fake and his headquarters was a psychic illusion. M.O.D.O.K. privately instructed Mentallo to play along in exchange for learning the full scope of his scheme.
As M.O.D.O.K. outlined his plans, Mentallo considered betraying his employer after acquiring the Hypernova. A.I.M.'s current Scientist Supreme Monica Rappaccini had put out a giant bounty on M.O.D.O.K.'s giant head. Telepathically searching for a possible confederate among the other minions, Mentallo detected major psychic armor protecting the Chameleon's thoughts. The Chameleon's role in the plan was to infiltrate the Infinicide's fortress in disguise while Mentallo implanted him with false memories to fool the aliens' own psychic probes. Mentallo was suspicious of Chameleon, and got him alone to perform the psychic wetwork for the job. When Chameleon dodged a speeding car in Mentallo's presence, Flumm detected the telltale psychic signature of Spider-Man's "spider-sense." Thinking the hero had somehow infiltrated M.O.D.O.K.'s 
minions, Mentallo tried to blackmail the "Chameleon." Rather ironically, Chameleon turned out to be an Ultra-Adaptoid, a power-duplicating android under the control of Monica Rappaccini, the very woman to whom Mentallo had intended to betray M.O.D.O.K. Instead, she had her Adaptoid blast Mentallo before he could reveal her deception to M.O.D.O.K. [Super-Villain Team-Up: M.O.D.O.K.'s 11 #1-5]
Mentallo had seemingly been burned alive by the Adaptoid's Human Torch power, so he likely used illusions to avoid the full force of the attack. When the Avengers began fighting each other over the Superhuman Registration Act, Mentallo was one of many members of the super-villain fraternity to whom Parker Robbins reached out. Robbins, known as the Hood, saw a rare opportunity to organize super-criminals while the heroes were at odds. Mentallo and many others chose to become part of the Hood's syndicate. [New Avengers (1st series) #35] After Norman Osborn took over the Initiative and the Act, he partnered with the Hood and negotiated even 
greater benefits and cooperation for the syndicate. Clint Barton of the unregistered Avengers tried to kill Norman for besmirching the Avengers' name, but was captured. Osborn borrowed Mentallo from the Hood to probe Barton's mind and find the rogue Avengers' hidden base. While Osborn was out hunting, however, Mockingbird and several Avengers infiltrated the H.A.M.M.E.R. Helicarrier to rescue Barton. Flumm was knocked out with one kick by the 'Bird, and Barton was freed. [New Avengers Annual #3]
Mentallo spent some time in prison after Osborn's fall from grace. He was at the Raft when a team of future heroes known as the New Defenders forced their way inside and kidnapped Doctor Doom from holding. His psychic powers allowed him to see what the Defenders intended to do and why, but he only gave Reed Richards and the authorities cryptic hints of what was to come in order to amuse himself. [Fantastic Four (1st series) #558] Mentallo tried to break out not long afterwards, but he was stopped by Doctor Pym and the recruits from Avengers Academy. With his helmet, Mentallo was powerful enough to temporarily turn the Avengers and their students against each other. However, he was caught off-guard by the dinomorph Reptil shifting into a purely instinctively intelligence, and was nearly ripped to shreds by the teenaged dinosaur hero. [Avengers Academy #6]