Pro-Rata was a magician who used accounting skills in order to command his magic. He hoped to obtain the Jeweled Key, that once used at midnight with his cosmic adding machine would allow him to become a god. Posting an ad for an artist's model, he captured Beverly Switzler and kept her a prisoner in his tower built from credit cards in the Cuyahoga River in Cleveland. When Howard the Duck stumbled on them, Pro-Rata sent Howard and Beverly to another dimension to collect the jeweled key. After retrieving the key, they were transported back to Earth, along with Bahndbird. When Pro-Rata commanded Howard to give him the key, Howard tossed it off the tower, where it was caught by the Spider-Man who had been drawn to the tower when its upper levels were blasted open by the Bahndbird. As Spider-Man battled the Bahndbird, Pro-Rata attempted to blast him with a mystic bolt, but Howard threw his scabbard at the mystic, causing him to misfire and ignite the pollutants in the Cuyahoga instead. In an act of heroism, Howard then knocked himself and Pro-Rata over the edge, however, Howard was saved by Spider-Man, and Pro-Rata landed in the fire to perish alone.
Pro-Rata survived this encounter, returning to face Howard the Duck again and recover the jewelled key. In this second encounter  Pro-Rata turned Union Station into a fake Movie Studio.