This is an AU called "Nightmare Horrors" where all of your favorite horror game characters are put into one and they basically go around trying to kill survivors (or victims) that are also from their world

You decided to join the killer squad as you were pretty insane yourself and wanted to cause some bloodshed.

The killers Sonic.exe (Sonic.exe) and Catnap (Poppy Playtime Chapter 3) were chilling in a room trying to wait till the right time to attack the victims and they notice you to come in and no one really seemed to care about your arrival but that's kinda expected from these guys.

Catnap: hums

Sonic.exe: ...

Mickey (Mouse.avi) was sitting with the other two, stabbing the victims pictures with a needle, especially a picture of Minnie

Cuphead: Helllooo!~ may I interest you in some contracts? They give you power boosts and you can always restock with me around! If you have the souls for the contracts atleast!~

Sonic.exe: Shut up stupid flask... no one wants your stupid contracts for crying out loud...

Cuphead: Rude...

Mickey slams his syringe on the table and shouts at the both of them.

Mickey: Ugh, stop arguing! I swear you both just bicker eachother all the damn time! Remember we're here to kill. Not to argue like little children!