Spike

Spike, given as Supaiku in Japanese, is the Quirk carried by Soga Kugisaki in the Vigilantes spin-off. It falls under the Transformation type at close range, opening the series in Chapter 1 and animated in Episode 1.

The name is shared with a villain from the U.S.J. Incident, who is a separate subject entirely. Fans have noted the concept echoes Marvel's Wolverine, another character who pushes claws out through his knuckles.

The ability pushes sharp growths out through the user's body. At baseline they measure about as long as his own fingers, with no established upper bound on their reach, and he appears restricted to three per hand or foot.

Each one is a metallic-looking cone that tapers to a fine point. They deploy and withdraw like claws, sliding out from between his knuckles and vanishing again, and the same trick works on his feet, presumably emerging between the toes.

The Trigger drug rewrites those limits. Under its influence the Quirk goes porcupine, with quills erupting across his head and neck, down his back, and out along both the upper and lower arms, running far longer than he could normally manage. Their striking power climbs to match: concrete fractures and shatters under a hard enough blow. None of it lasts, and everything reverts to normal strength once the drug leaves his system.

He reached the same territory without chemical help when Stendhal put his life in real danger. Soga underwent a transformation across his entire body, gaining height, his face reshaping into something porcupine-like, and spikes sprouting from the same locations Trigger had produced them. The anime added a further ability at that stage, letting him shoot the spikes outward.

Soga Kugisaki is the only known user. His arc with the Quirk runs from ordinary knuckle spikes, through the artificial escalation of Trigger, to a desperate full-body change forced out of him by a lethal encounter with Chizome Akaguro.