The D-Type Converter was an energy-converting device modeled after the technology used by Galactus to speed up the process by which he devoured planets. It was built by Beavertron Incorporated on Daggett's World. It siphoned life energy from the planet to convert it into power, and it was then sold by Castor Gnawbarque III to neighboring systems, marketing it as clean, geothermal energy.
With use of the D-Type Converter slowly desertifying the planet, its inhabitants sought the help of the Guardians of the Galaxy to destroy it. In response, the tycoon hired a splinter group of Guardians lef by Gamora to provide security and prevent any sabotage attempts.
Marvel Boy infiltrated the D-Type Converter but was intercepted by Gamora's Guardians. A skirmish ensued and Marvel Boy used his Nega-Gauntlets to swap places with Hercules. During a fight against the Prince of Power, Hercules used the momentum of Prince's attack against him, lunging his opponent into a component of the D-Type Converter that was vital to its energy containment. With its self-repair systems also compromised, the D-Type Converter began to set off. In the meantime, Marvel Boy had snuck into Gnawbarque's office and forced on him his pair of Nega-Gauntlets. Hercules used his pair of Nega-Gauntlets to switch places with Gnawbarque and escape alongside the opposing Guardians from the destruction of the D-Type Converter, leaving the tycoon stranded inside the device with only seconds before it exploded.