Board Thread:General Discussion/@comment-26006155-20181123023529/@comment-26006155-20181123153602

Ambassador, Undertale specifies that the creepy voice Frisk hears in the True Lab Elevator is one he's never heard before.

Frisk has already heard Flowey's voice, a LOT.

Gaster's invisible touch also permiates most of Undertale in the background. It's between True Lab entires 16 and 18 that Gaster's Lab Entry 17 should appear, which talks about a very dark experiment. Filed been 16 ("no No NO NO NO NO") and 18 ("The Flower's Gone").

So Flowey may actually be one of Gaster's experiments, and have a more complex backstory than we know.