As you hear footsteps among the ends of Waterfall, you overhear a conversation from not too far away "i-i know, papyrus, i know... but this is the only way i can get the human to stop, bro.. i need to kill off everyone, i need their exp so i'll be strong enough.. i-i need to kill the human, paps.. what else is there for me to do..?" Sans turns to face you, with a look of surprise "... well, well.. it's you... this should be entertaining..." Sans begins chuckling to himself