Artifact Room

The  is a secret location found in Waterfall after solving the Piano Puzzle.

Description
The room is a simple room that holds a legendary artifact on a pedestal. The artifact itself is red and spherical in nature.

Attempting to take the artifact will give the message, "You're carrying too many dogs", and the Annoying Dog will appear in the inventory for this room only. When the Annoying Dog is dropped or used, it will absorb the artifact and walk off the right of the screen, leaving a Dog Residue in the inventory.

Interacting with the pedestal after the artifact is gone will bring up text saying "The artifact is gone".

Trivia

 * This room makes a brief appearance in the Steam Greenlight Trailer for Undertale but had no collision. Sans asks the protagonist if they have noticed the room has no collision then Papyrus comes onscreen to ask if he can be in the trailer.
 * If the Annoying Dog is removed from the protagonist's inventory through unconventional means, such as opening the Dimensional Box in the debug menu and placing the Annoying Dog there, interacting with the artifact again will display the message: "This will never happen."
 * Using the Cell Phone to call Papyrus will bring up dialogue that foreshadows the Annoying Dog.
 * According to a call with Undyne, nobody else has ever solved the piano puzzle before the protagonist does. She will then talk about how she's been waiting a long time for someone to solve the puzzle but will then try to play it off. Calling her again will bring up dialogue saying that she guesses that she has to find a new mystic artifact.
 * Attempting to call Toriel in this room while the Annoying Dog is in the inventory will bring up a message stating that "The ringing is coming from inside your inventory".