Hydra is a fictional terrorist organization appearing in American comic books published by Marvel Comics. The name "Hydra" is an allusion to the mythical Lernaean Hydra. The organization's motto references the myth of the Hydra, stating that "If a head is cut off, two more shall take its place", proclaiming their resilience and growing strength in the face of resistance. Originally a Nazi organization led by the Red Skull during World War II, it is turned into a Neo-Nazi international crime syndicate by Baron Wolfgang von Strucker once he seized control. Hydra agents often wear distinctive green garb featuring a serpent motif. The organization is one of the recurring threats fought by the Marvel Universe superheroes and the intelligence organization, S.H.I.E.L.D., who regularly foil Hydra's plans for world domination.