You were Outer Sans, you were got harmed by Killer Sans... but somehow you(Outer Sans) hadn't died... you(Outer Sans) woke up what seemed to be Nightmare Castle... Killer Sans's room as you(Outer Sans) see Killer Sans laying besides you(Outer Sans)... 1st Soul stage... As he seemed to be flirty...

Killer Sans: Hey, Outer me.

As he grabs your(Outer Sans's) chin and pull you(Outer Sans) into kiss as you(Outer Sans) pull Killer Sans into a kiss. It was pretty weird since you(Outer Sans) and Killer Sans are Skeleton Monster...