Spike allows its user to make spikes protrude from their body. The spikes produced naturally appear to be roughly as long as its user's fingers, though it is unknown just how long they can extend to. Initially, the user only seems able to generate three spikes per hand or foot.
The spikes appear to be metallic in makeup and are sharp to the point. They are akin to claws, popping out from, and then retracting back between the knuckles of the user's hands. Additionally, they are also able to be released from the user's feet, presumably between their toes. They appear to be cone-shaped in nature.
When under the effects of the drug Trigger, this Quirk is greatly amplified. When used, Trigger gives this Quirk a porcupine-like physiology, with a large number of quills extruding from the users back, neck, upper arms, forearms, and head. These quills are dramatically longer than the Quirk usually allows. The spikes appear to be even more destructive, able to cause concrete to crack and even shatter when used with enough force. However, these effects are only temporary and are reduced back to the normal strength once the drug's effects have worn off.
Later, when Soga's life was endangered due to Stendhal he manages to take on a full-body transformation, growing taller and altering his face to become porcupine-like, additionally he grew spikes in the same places that he previously had under the effects of Trigger.
- This Quirk may be a reference to Marvel's Wolverine, who has a similar ability to extrude claws from his knuckles.
- My Hero Academia: Vigilantes Manga: Chapter 1 (p. 17-30).