Alphys is the head scientist of the monsters underground. She experiments with a human "substance" called Determination. While trying to give monsters the ability to persist in soul-form after their bodies have died, she inadvertently resurrects Asriel. She injects Determination into one of the flowers in the palace gardens. If you can recall, this is the spot where Asriel died. Consequently, Asriel wakes up as a flower in the garden, becoming the game's main antagonist, Flowey. Players might ha...