Sludge Form

Sludge Form is an unnamed Quirk possessed by Sludge Villain.

Description
The Quirk allows Sludge Villain to transform into mud-like form, in which he is immune to most physical attacks. He is apparently capable of taking control over body of a person and their Quirk by engulfing them in his liquid body.

Shockwave of All Might's punch was however capable of scattering his liquid form and rendering him unconscious, allowing Toshinori to store him in a bottle.