Pipe Room

The Pipe Room (Japanese: 配管室 Piping Room) is a room explored in Area Four of Luigi's Mansion.

Story
After obtaining the Key from the Armory, Luigi accesses the Pipe Room. Immediately, some green Flying Fish start attacking the ghost hunter. To make matters worse, some Red and White Grabbing Ghosts appear as well. Within the cramped room, Luigi manages to separate and capture every one of the ghosts inside his Poltergust 3000. The Pipe Room becomes illuminated, but Luigi does not receive a Key. The plumber notices a frozen barrel giving off an icy mist. As Luigi approaches it, an Ice Elemental Ghost flies out. After Luigi captures it, he uses the Ice Element to freeze the river of water flowing through the room. Successfully having made a bridge to the other side, Luigi turns a red wheel on one of the pipes, stopping the waterfall on the other end of the room. Luigi walks to where the waterfall once was and claims the Key to the Cold Storage, allowing him to continue his quest to find Mario.

Description
The Pipe Room is pretty filthy, containing an ancient crate, a bucket, and the aforementioned frozen barrel. The river of water is untouchable until Luigi freezes it.

Trivia

 * The Pipe Room and the first floor Washroom are quite possibly the only necessary rooms in the game which are never required to be lit up (unless of course the player is trying to catch all fifty Boos), as Luigi can completely ignore the Grabbing Ghosts, freely freeze the river of water and turn the waterfall off to obtain the key to the next room.