Well, it could be a really intense encounter. Maybe there would be a battle of wits as they try to figure out each other's motives. Since Horrortale Sans has been through a lot in his own universe, he might be more cautious around the other Sans. And the other Sans could be either curious or a bit scared of Horrortale Sans's appearance and the aura of horror that surrounds him.
The other Sans could also be very interesting. If it's a Sans from a more light - hearted universe, his reactions to Horrortale Sans would be a sight to behold. He might be shocked, intrigued, or even try to help Horrortale Sans in some way. His attempts to understand Horrortale Sans's world and bring some of his own positive energy into the situation could create a lot of engaging storylines.
Frisk could be one of the characters watching. Given their role in the game, they would be interested in Sans' fight as it could impact their journey through the Underground. Additionally, Undyne might be present. She's a strong fighter herself and would probably be sizing up Sans' techniques, maybe even learning from him or being critical of his fighting style depending on her mood.
Well, in this fanfiction, it might show different perspectives of various characters seeing Sans fight. It could be really interesting to see how different characters react to Sans' combat style, whether it's his unique attacks or his strategic moves during the fight.
One interesting 'sans fight fanfiction' story could be about an alternate universe where Sans has different powers during the fight. For example, he might be able to manipulate time in a more extreme way than in the original game.
Another great horrortale is 'The Doll in the Attic'. There's an old, porcelain doll that was left in the attic of a new house the family moved into. At night, the doll seems to move on its own and makes strange noises. The family members start having nightmares related to the doll, and one by one, they fall into a state of paranoia. It's a classic horrortale that plays on the fear of inanimate objects coming to life.
You can try websites like Archive of Our Own (AO3). It has a large collection of fanfiction, and you can search specifically for 'sans fight fanfiction' there. Just use the search bar and type in the relevant keywords.
One thing that makes it special could be the unique view it offers. Instead of just focusing on Sans fighting, it's about everyone seeing the fight, which gives a broader perspective.
In the fanfiction, a character might also react with confusion. Sans' attacks and his overall fighting style can be very unique and hard to understand. A character who is used to more straightforward combat might be completely bewildered by Sans' moves, not knowing how to counter or even react properly.
It's really hard to say. RWBY characters have a wide range of abilities and combat training. Ruby is super fast and has a powerful scythe. But Sans has his magic like his bone attacks and dodging skills. I think it would depend on the situation. If it's in an open area, RWBY characters might have an advantage with their long - range attacks. But if it's in a more enclosed space, Sans' teleportation could give him the upper hand.