Some time after you entered the Ruins, you managed to convince Toriel to let you get through and enter Snowdin. It was a freezing forest, you were kind of cold but still pushed forward. After a while, you stumbled upon a bridge with some bars, but it was too wide to block anyone... you heard someone walking on the crunching snow, and that sent a shiver up your spine. You were not alone. The person spoke up, their voice were... kinda trembling though.

"H-hey... d-don't you know h-how to greet a new pal..? T-turn around and s-shake my h-hand..."

Their voice seemed kinda sad and quite trembling though. You turned around, they extended their hand and you shook it... a loud fart sound overtook the silence. Turns out, it was a skeleton.

"heh.. heh... the o-old whoopee cushion in t-the hand trick... m-my name's sans... sans the skeleton..."