WOLVERINE

When Wolverine debuted in Incredible Hulk #180–181 (1974), his claws were not part of his body — creator Len Wein conceived them as mechanical weapons: telescoping adamantium blades housed in casings in the backs of his gloves. Wein admitted it himself in a 2009 blog post: "my original idea was for Wolvie's claws to extend from the backs of his gloves… Dave [Cockrum] and Chris [Claremont] definitely improved on that idea." It was Cockrum and Claremont who made the claws part of his body in Giant-Size X-Men #1 (1975).

For 17 years the claws' true nature stayed murky — were they implants from the Weapon X program? The answer came in two steps. First, Barry Windsor-Smith's "Weapon X" (Marvel Comics Presents #72–84, 1991) depicted the adamantium-bonding process and revealed the awful truth: beneath the metal, the claws were bone — a natural mutation. Then in X-Men #25 (1993), during "Fatal Attractions," Magneto ripped the adamantium from Wolverine's skeleton — and Logan popped a set of bone claws, proving once and for all they had always been part of him.

The retcon stuck. Bone claws became the cornerstone of his origin — first manifesting as a boy in the 1800s, as later shown in "Origin" — and Logan fought with nothing but bone from 1993 until Apocalypse restored his adamantium in Wolverine #145 (1999). In his earliest appearances, the claws were never even seen retracting — and they appeared to extend from his wrists, not his knuckles.