state, and when molded to a sharp edge, it can penetrate most lesser materials with minimal force. The Marvel Comics character Wolverine discovers an adamantium-laced skull in the character Apocalypse's laboratory and says it seems to have been there for eons. As a key component Adamantium appears in various Marvel Comics publications and licensed products, where it is found in: Ultron's outer shell Wolverine's skeleton and claws Sabretooth's skeleton and claws were laced with adamantium in a 1998 storyline. Captain America's second shield, alloyed with vibranium and steel The damaged bone of Bullseye's vertebrae Lady Deathstrike's skeleton and talons X-23's claws The Russian's body, following his resurrection by General Kreigkopf Other versions Secondary adamantium Marvel’s comic books introduced a variant of "true" adamantium, “secondary adamantium”, to explain why, in certain stories, adamantium was shown to be damaged by sufficiently powerful conventional forces. Its resilience is described as far below that of “true“ adamantium. Appearances of secondary adamantium in Marvel comic books include the casing of the supercomputer F.A.U.S.T., a suit constructed by F.A.U.S.T. and Blastaar for Stilt-Man, a retractable protective dome around Exile Island, and an army of Ultron duplicates. Ultimate Marvel In stories published under the Marvel Comics Ultimate Marvel imprint, adamantium is highly durable and can shield a person's mind from telepathic probing or attacks. It is a component of the claws and skeleton of Ultimate Wolverine and of the Ultimate Lady Deathstrike character. This version of adamantium is not unbreakable. In Ultimates #5, the Hulk breaks a needle made of adamantium. In Ultimate X-Men #11 (December 2001), an adamantium cage is damaged by a bomb. In Ultimate X-Men #12 (January 2002), one of Sabretooth's four adamantium claws is broken. Comparison with real materials Scientist David Evans argued that as adamantium "is considered to be a very dense and indestructible metal" the most suitable real material to model it would be "[o]smium, the densest known metallic element". See also Unobtainium Vibranium References Fictional metals Fictional elements introduced in the 1960s