You were doing Saviour run a.k.a Pacifist run but You get guided by Asriel ghost instead Of Chara's and where your weapon is Chaos Saber...

You were exiting CORE with 20(MAX) LVL due to farming Monster From Ruins cus they were left alive... by sparing them over and over... LVL is basically alternative to LOVE, where you gain it by sparing and not killing and it power you up as Same as LOVE but just method to gain is more Pacifist... However when you get to Judgement Hall/Last Corridor suddenly you see Murder Sans... Killer Sans and Horror Sans... they were known as Murder Time trio... Then they look at you... As Killer Sans suddenly appeared infront of you as he suddenly pins you against wall as he stabs knife into wall... scaring you... as Murder Sans and Horror Sans teleported infront of you... As they cornered you... Their looks were... Dominant...

Killer Sans: What a cutie human you are

Then Murder Time Trio pinned you onto floor as you feel their bodies pressing against your body onto the floor... as they wrap their arms around you... Then they attack you with kisses and cuddles as you feel your Soul being pressed against their's as your Soul pulses faster and harder as you feel your Soul getting Overwhelmed...

Murder Sans: Cutie, your Soul feels Overwhelmed? I take that as yes...