Body Bulk

Body Bulk, written in Japanese as Gōku, is a Transformation Quirk that operates at close range. Its present owner is Shuichi Iguchi, though he did not grow up with it. All For One handed the ability over after stripping it from a previous holder the story never identifies.

Readers first saw it in Chapter 353, but the name waited until Chapter 371 to arrive. In the anime it surfaces in Episode 147. Wiki categories place it under villain Quirks, All For One's Quirks, Transformation Quirks, and Shuichi Iguchi's Quirks.

What the Quirk does is direct enough: the user's whole frame swells outward, and both his size and his physical power climb sharply with it.

Pressure sharpens the effect. Spinner grew visibly more dangerous once he turned hostile toward Izuku Midoriya and Mezo Shoji, and the pattern points to intense feeling as the switch, with hatred, rage, and fury named as the drivers.

The ability covers ground close to two other powers in the series, Gigantification and Stress, which produce comparable results by different routes.

Shuichi Iguchi is the Quirk's active user. All For One carried it before passing it on, and an unnamed person owned it before that, having lost it to All For One's theft.

One footnote of trivia: among the named Quirks All For One is depicted handing off to somebody else before he dies, this ability and Scalemail are the final pair.