okay ... let's start by parts.

1- my idea is crazy

2- my idea contains Yaoi

3- The story takes place in Underfell with the following characters: UFSans, UFPapyrus and UFGrillby

Below is the chips of the characters

Sans- he is the older brother of Papyrus and is responsible for cleaning the house and doing the food for Papyrus (he always calls his brother "boss") and despite trying to be scary and mean it is only a skeleton short and cute

Papyrus- he is the younger brother of Sans and is one of the security of Striper house belonging to Grillby. He always evil is his own brother but, in fact, he maintains a sexual relationship with him, and more than not show he cares about Sans

Grillby- he is the owner of Striper Underfell home and is interested in Sans when he sees for the first time and plans to kidnap the brother of Papyrus to turn on "your favorite" the stripper's house (that means he wants Sans for this to be his sex toy )

The story:

It begins with the UF Papyrus getting ready to leave for work while the UF Sans did the crazy breakfast, Papyrus out so rushed that he forgets to bring lunch day Sans then decides to take lunch from his brother to him.

Sans arrives at work of Papyrus, which has not yet opened, and sees him talking to the UF Grillby and go there saying the Papyrus forgot his lunch at home and he decided to bring it to him. Grillby looks at Sans with a face of someone who is planning something.

Papyrus speaks some bad things Sans Pro and sends him to leave but, deep down, he is very happy to see that Sans brought lunch that he had forgotten to him. Grillby question who was that for Papyrus and this argues that it was his brother who is good for nothing and will work leaving the Grillby alone who thinks that "good for nothing" would be perfect for the new personal pet for him.

The club opens and customers begin to arrive and the staff starts working, Papyrus see Grillby getting ready to go out and asks where he is going, Grillby replies that he's going to get "new pet" that he could for himself and speaks this with a well pevertida face and suspicion for Papyrus not care much and continued with his work.

Grillby actually went to the home of Papyrus and touches the door, Sans serves. Sans was wearing an apron as she was cleaning the house and Grillby, seeing Sans thus not very secure and the flames it increase in intensity causing mop the Sans holding caught fire. Grillby calms down and apologizes to him and asks if he can get. Sans let them in and closes the door of the house.

Grillby sitting on the couch and Sans offers him a cup of coffee and asks him what he wanted. Grillby rises and Corners Sans against a wall and holds the leash he has neck and says "I want you". Grillby increases the intensity of the flames causing the Sans be so hot, but so hot, he faints because of it. Grillby takes the Sans in her lap and leaves carrying the Sans. Papyrus feel that something was not right when the lunch that the Sans brought it falls all over the floor, it was spaghetti but he thinks it was nothing but just a wrong feeling and back to work.

The Papyrus of the work shift ends and he returns home when he realizes that his front door was not locked it comes up screaming and cursing Sans saying he forgot the door unlocked house when he sees the cup broken coffee and coffee spilled on the floor and immediately climbs the stairs screaming Sans and see that he is not in any room of the house. He is raging.

Meanwhile, Sans begins to wake up in a different location, he was in a very chic room and that seemed to be pretty expensive. Sans wakes up frightened and sees that now he was only wearing his white shirt, and was arrested by a very strong chain on her collar that was stuck in the room wall and, try as he might release the chain, he could not, and was when you heard the voice of Grillby saying that it was useless and that he was now the owner of him.

Sans says he belongs to no one when Grillby holds the "leash" and says that it was a lie because he knew the Sans slept with Papyrus, maybe every day. Sans begin to feel fear of Grillby stealing a skeleton tongue kiss.

Meanwhile Papyrus follows like a madman looking at Sans when he remembers seeing the Grillby tidy and coming out and saying that he would take his pet animal and remember, especially the guy who Grillby made to see the Sans for the first time and his face when he said the reason for his departure. Papyrus raging goes to the stripper club.

Papyrus enters the club putting down the door and calling for Grillby, customers begin to flee to see that Papyrus destroying everything around and because of demonic aura it. He continues to rage until grabs the Mettaton, who was a waitress and asks where Grillby was and he says he saw the Grillby up to his room saying he did not want to be disturbed under any circumstances and that he was carrying something wrapped and hidden in white fur coat it. Papyrus goes to the Grillby room.

Papyrus places the wall Grillby room below and see Grillby sitting on the edge of the bed, covered only by covering bed and smoking a cigar quietly. Papyrus was about to attack him when he hears the faint Sans voice from the other side of the bed, Sans had some burnt bones, nothing not too serious, still caught by the collar and chain and note clearly what had happened there. Papyrus is in psychopath and talks so the Grillby is a dead monster but Sans holds by the hand and says that he just wants to go home. Papyrus and unwillingly, take the Sans carefully and copper with an indoor and out, looks at Grillby and says that if he touches again in Sans he would kill a well painfully in and out of there taking the his brother in arms.

Grillby takes the cigar from his mouth, blows the smoke out and with a smile on his face says that it was only a beginning and that the Sans would return to him willingly as he knew the secret that Sans always hid from Papyrus and the Sans does not want to reveal to anyone, especially for Papyrus his brother.

End of part 1

Part 2: the secret of the Sans is revealed. How will Papyrus leader with this? And Sans Grillby met again. A storm of emotions final appears! Who Sans will be in the end? This part is the final.