Seven. Seven human souls. With the power of seven human souls, our king... KingASGOREDreemurr... ... will become a god. With that power, ASGORE can finally shatter the Barrier. He will finally take the surface back from humanity... And give them back the suffering and pain that we have endured. ... Understand, human? This is your only chance at redemption. Give up your soul... Or I'll tear it from your body.
— Undyne first monologuing to the protagonist, and afterward, proceeds to attack them
"Undyne" is the 30th track in the Undertale Soundtrack. This track plays during the first encounter with Undyne. While hiding in the tall grass at the feet of a cliff, Undyne hears the shuffling of the brush and aggressively looks for trespassers below the cliff.