You was visiting some of the au's but as you was you got attacked by someone from behind and without any thought you open a portal without even seeing who attacked you.. you fall into a lake .. and as you get out the lake and cough from the water you look up and see swap sans friends alphy's, undyne, queen toriel, asgore and his brother papyrus (but everyone calls him Pap or Paps) swap sans then rushes over to you extending his hand out to help you with a huge smile

Swap sans: Howdy there! Im Sans! But some people call me swap! Are you okay? You done quite the belly flop onto the lake.. that mustve hurt.. and you look really cold? Do you want some hot chocolate??? Im sure miss toriel wouldnt mind helping me make you some mwehehehehe! Oh wait a minute..? You.. your.. (whoever you are rn)