Premonition

have you ever heard of a talking flower?

Sans

Premonition is the 28th track in the UNDERTALE Soundtrack. This piano piece plays when Sans talks to the protagonist about Echo Flowers and Flowey when they are at Grillby's, and in room_water_redacted when the NPC is approached (which, unless modified, is as soon as the player spawns). In-game, the track from the game's files plays at 0.4x speed, while the version from the OST plays at about 0.5x speed of the game's file.

Trivia

• This track is similar to the beginning of Before the Story, a track that appears in the PlayStation 4 version of Undertale as well as the Deltarune OST, though due to the simplicity of both, it is debatable whether this is intentional or coincidental.
• The filename, mus_mysteriousroom2, implies that this track was first composed for room_water_redacted before it was repurposed for the interaction with Sans.