Boil Release: Skilled Mist Technique

Mei Terumī the Fifth Mizukage uses her Boil Release to create a cloud of mist which she releases from her mouth. This mist has corrosive properties. The technique has an inherent disadvantage in that its effects are indiscriminate, limiting its usage to areas that do not presently contain allies until the attack is completed. In the event that the mist escapes the containment area, thus putting others in danger, the Fifth Mizukage has suggested that the technique can be sufficiently manipulated to limit its acidic qualities to safer levels.

Though the mist is corrosive to all around it, the user seems to be immune to it, as Mei used it in an enclosed area without endangering herself.