After being fired from his job, scientist Mason Harding fell in with the Royalist Forces of America, and was convinced to design the Madbomb for them because he needed the money. The Madbomb was a sonic device which caused people to go insane when affected by it, making them run wild and attack each other. A Madbomb the size of a fingernail--"Peanut"-- could affect people in the same room; a Madbomb the size of a grenade--"Dumpling"-- could affect an entire neighborhood; the largest Madbomb, "Big Daddy," could have potentially affected all of the United States. 
A Madbomb which was the size of a grenade was set off in New York City, causing chaos throughout the city. Captain America managed to find it and smash it with his shield, returning everyone to normal. He and the Falcon then attended a briefing with Henry Kissinger, where they learned about the devastation brought to Miner's Junction by Peanut and to River City by Dumpling, and were alerted to the threat of Big Daddy.
Their hunt for the bomb was fruitless, as they were only able to find where it was constructed. 
After Captain America and S.H.I.E.L.D. had captured the compound where Harding's daughter was being held, Harding turned against the Royalist Forces, and used a miniature Madbomb to make the men guarding him shoot at each other. He then went to Captain America and the Falcon, offering them the means to be immune to the Madbomb's effects, and to help them stop "Big Daddy." Meanwhile, William Taurey gave word for "Big Daddy" to be activated.
The Falcon then journeyed to the Taurey Towers Building in Philadelphia, where "Big Daddy" was concealed within the top of the building. It had already been activated by the time he fought his way inside, but he pulled the device's lever to "maximum" level, causing it to explode. 
Later scrapped, this Madbomb's dismantled components were stolen from their military custodians by La Tarantula and his accomplishes. They were stopped by Captain America.
The Sons of the Serpent with the Assistance of Elite member Cheer Chadwick constructed a new Madbomb that was destroyed before it could be put to use. Like previous bombs people could be immunized to its effects.
In the aftermath of the Serpent's rampage, updated designs of previous Madbombs were seen, produced by Hydra scientists working for their new Queen, along with new version. These much larger and mobile "Omega" Mad-Bombs were crated by the Hydra forces to continually broadcast their effect into the television broadcasting networks. They were destroyed with the assistance of Iron Man.
- 13 Appearances of Madbomb (Item)
- 1 Minor Appearances of Madbomb (Item)
- 1 Media Madbomb (Item) was Mentioned in
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- Item Gallery: Madbomb (Item)