Water Peck, played by William Atherton is a character from the 1984 film Ghostbusters.
Peck is an investigator for the Environmental Protection Agency. The first person he meets with is Peter Venkman, who doesn't take him seriously and instead insults him.
Peck makes it a personal mission to shut down the Ghostbusters facility, especially their containment unit housing all the ghosts they've caught. He secures a court order and brings the police with him to shut down the grid.
Afterwards the containment unit has a catastrophic explosion, releasing all the ghosts they managed to catch up to that point. The Ghostbusters are arrested as a result.
When New York is under attack by countless ghosts, Mayor Lenny Clotch calls the Ghostbusters to his office asking what's going on. Peck and The Ghostbuster get into an argument and after a stirring speech from Venkman regarding just how many registered voters Mayor Lenny can save if he releases them, Peck is escorted out of his office.
Peck is later seen in the middle of the street after the Stay Puft Marshmallow Man is melted and torrents of melted marshmallow falls onto him.