Powderkeg was created by Dwayne McDuffie and Doc Bright in 1989 and first appeared in Captain Marvel #1.
Powderkeg is a third-string villain. He is super-strong, pretty close to invulnerable and sweats nitroglycerin (or a nitroglycerin-like substance).
Not too much is known of Powderkeg before he became an agent of Ms. Ramos. Powderkeg and his crew of Portuguese terrorist hijacked a cargo ship called the Tea Cake whose captain happened to be Monica Rambeau. The terrorist killed her crew and held several passengers hostage. Rambeau at the time had temporarily lost her powers and was no longer Captain Marvel. Rambeau managed to take down two terrorist and change into her Captain Marvel costume. She confronted the rest of the terrorist and they surrendered without a fight because they believed her bluff. Powderkeg blasted through a door and made a hole in the deck with his explosive punch. Rambeau fell in and Powderkeg jumped down after her. Rambeau managed to drop several tons of wheat onto Powderkeg and then she freed the rest of the passengers. Powderkeg would escape from the wheat pile and cause a huge explosion on the ship. Rambeau decided to get back onto the ship and try to rescue Powderkeg. She finds Powderkeg tearing up the cargo area with flames surrounding him. Powderkeg refuses to leave until he finds a certain box.
For some unknown reason, Rambeau regained her powers at that precise moment and was Captain Marvel once more. She finds Powderkeg and a brief fight ensues on the burning ship. Powderkeg gets knocked out by Captain Marvel and she uses his explosive touch to break through the ship’s hull so they can escape. Powderkeg fails to deliver a certain package to Ms. Ramos and is apprehended by the authorities.
Powderkeg has superhuman strength, durability and resistance to injury. He also has the ability to secrete nitroglycerin through his sweat glands. He can cause small explosions when he slaps his hands together. Powderkeg will explode when he hits his enemies or whenever he gets hit.