The Midgard Serpent, sometimes called the World Serpent, is a fictional character that appears in comic books published by Marvel Comics. The character is based on the creature of the same name from Norse mythology, and is also referred to by the name "Jormungand".
Being aware of the prophecy regarding his son's death, Odin cheats fate during a false Ragnarok by replacing Thor with a surrogate known as Red Norvell, who dies battling the Midgard Serpent. Many years later, while still suffering from the Curse of Hela - which made his bones as brittle as glass but unable to heal and unable to perish - Thor meets the dragon Fin Fang Foom, who is revealed to be the Midgard Serpent in disguise. After an epic battle, Thor kills Jormungand, but is reduced to pulp himself.
The Midgard Serpent is apparently resurrected years later, as Morgan le Fay summons it to Earth to distract the Avengers while she abducts the Scarlet Witch. The Midgard Serpent later makes a reappearance during the events of Ragnarok.