Waterfall Piano Puzzle (Artifact Room)

Waterfall Piano Puzzle is optional but useful for Dog Residue farming and Temmie tuition.

Steps

1. Pick up an umbrella in the rainy Waterfall section.
2. Give the umbrella to the statue to hear the melody.
3. Return to the piano room and replay the opening notes of that song.
4. Enter the newly opened door to the artifact room.

Artifact and dog

Trying to take the artifact fails because “too many dogs” are in your inventory. Check ITEM, drop or interact as prompted, and let the Annoying Dog absorb the artifact. You receive Dog Residue.

What Residue does

Using Dog Residue fills empty inventory slots with more residue and sometimes Dog Salad. Sell surplus at Temmie Village; keep one residue to continue the loop.