This monster has never revealed her true name, lest she fall into involuntary servitude to those who might summon her. During the sixth century A.D. she and her son Grendell lived in the marshes and lakes of Denmark. Grendell ravaged the land around Heorot Hall for years, devouring all he met until the Scandinavian prince Beowulf came to King Hrothgar's aid. During one of his raids on Heorot, Grendell was seemingly mortally wounded when Beowulf tore his arm off. In revenge, the mother attacked the hall and killed one of Hrothgar's retainers. Beowulf tracked her to her watery lair and, attempting to slay her with a powerful sword (possibly Excalibur) that he found in her hoard, imprisoned her in a floating underground prison. Long afterward a descendant of Beowulf's people wrote the old legends into an epic poem celebrating the hero's achievements for the ages.
Centuries later, the Dark Elves of Asgard summoned the one-armed Grendell to kill Thor while he forged a suit of magic armor - created to counteract Hela's curse which made his bones brittle - as they feared that the iron in the armor would allow him to slay them. Grendell had nearly slain Thor when Loki teleported the broken hero away for his own dire amusements.
Recently, the wizard Merlin Demonspawn (formerly Maha Yogi) located the mother's prison and sought to free her so she could lead him to the lair of the dragon that had slain Beowulf, hoping to find the legendary Holy Grail. Needing the blood of one hundred virgins to free her, Merlin opened the Comic Book Castle store and amassed a loyal clientele through huge discounts and P.R. stunts. Finally, Merlin held a 'spectacular giveaway' promotion at his store and enchanted the crowd of a few hundred customers into cutting their hands and bleeding on the floor, thus freeing the mother; however, Merlin's chief business competitor Marlo Chandler-Jones convinced the monster that he had freed her and offered her the lives of his customers only to gain access to the Grail. Angered by being treated as a lackey, she refused to cooperate and left Merlin to his fate at the hands of Captain Marvel (Genis-Vell) and Moondragon. While marveling at the sights of modern Los Angeles, the monster met agent Mordecai P. Boggs and signed a five-year contract with the FWW as wrestler Big Mother, vowing to "eat her opponents alive."
