Tail

Mashirao Ojiro's Quirk is a Mutant type of close range, first appearing in Chapter 8 and Episode 5. What it gives him is a prehensile appendage growing out of his lower back.

His version runs heavy. It outsizes every one of his ordinary limbs in both length and width, and it finishes in a blonde tuft matching the hair on his head.

Treat the appendage as a third limb and the picture is accurate. It breaks metal objects, wraps around opponents to hold them, and bears Mashirao's full weight without strain. He has pointed with the tuft at its tip the way a person points with a finger, though whether it manages anything finer than that has never been confirmed.

Training built it up. He spent long stretches hammering the limb against a hardened Eijiro Kirishima, and every impact left it stronger and more durable than before.

The drawbacks are ordinary ones. It bruises and tears like any other part of him, and because the mutation is permanent he struggles to sit down or lie flat. Off-the-rack clothing does not fit either; his wardrobe has to be cut for his anatomy.

Mashirao alone uses Tail. He blends it with martial arts to fight fast and acrobatically at close quarters, driving the limb into opponents directly or leaning on it to steer his own momentum. Ectoplasm has flagged a flaw in this: people born with tails tend to settle into repeatable movement patterns, and Mashirao reads as predictable because of it.

Mobility is where the Quirk shines. A hard slap against the ground launches him over obstacles on the floor, and he can hang from pipes or poles by coiling the limb around them. Two Ultimate Moves formalize the approach. Tornado Tail Dance spins him through the air, sweeping everything within reach, first used to destroy Pony Tsunotori's remote-controlled horns at the Joint Training Battle. Swamp Smack Spin is the defensive one, a flat horizontal rotation with the limb extended that shoves back anything nearby; he escaped Juzo Honenuki's Softening with it.