Water Gun

Water Gun (ミズテッボウ, Mizutebbou) is a C-Class hero for the Hero Association.

Appearance
Water Gun is a young man wearing a black wet suit, goggles and a white swim cap with the kanji for "water" (水, Mizu) on it

Super Fight Arc
Water Gun is encountered by Saitama and tells him that he was defeated and that the monsters had left 30 minutes prior.

Abilities and Powers
As a C-Class hero, it can be assumed that Water Gun isn't a very powerful individual. Since his rank is unknown, it is unknown how he compares to other heroes in his class.

Equipment
Water Gun: His titular weapon. It could be presumed this makes him effective against fires and fire-based monsters, though his C-Class level suggests otherwise.