Shining: Hey flash! nice costume of the flash!  
Flash: yeah! i dont what to wear! so i let twilight take for me! plus i a crimenal scum bag to capture! and nice costume of captien america!  
Shining: thanks! cadance want and is mom who made it! but is i wander what twilight and cadance will wear?  
Flash: twilight say is two character of the same game but she not tell! the thing she say is form a fighting game! hmm but who?  
Pinkie: the character are demon girls! and the twilight and cadance are ready!  
Cadance: hello captien america!  
Twilight: hello the flash!  
Shining: ga?  
Flash: wha?  
Twilight: ready for nightmare night boys?  
Cadance: if you are not , we will go wont you!  
Flash: we are!  
Shining: yeah!  
Cadance: good! are you ready for our bed play alter nightmare night shining?  
Shining: of course!  
Flash: bed play?  
Shining: you will get it! me and cadance we do this every nightmare night alter we get our 18 years!  
Twilight: yeah! and i want to do it with my special pony!  
Flash: bed play?…oh! sex game!  
Velvat: yes! what i look?  
Twilight: we sex mom but why you take the same every years!  
velvat: oh, your father love his little redhood! and i love my very bad wolf!  
Night light: yeah! i am a very bad werewolf!  
Shining: more like a pet!  
Twilight: yeah!  
Cadance:…..wow! we better go, right shining! and thanks you Pinkie to take flurry for her first nightmare night!  
Pinkie: is ok! what you think of my costume of lolipop saw?  
Twilight: is good! is my costume you use right?  
Pinkie: yes!  
Flurry heart: what you think of my sailor chibi moon costume, everypony?  
Cadance: ohhhh! you are so cute!  
Luna: and i sailor moon! (flurry and luna do the pose)  
Twilight: awww! so cute!  
Cmc: were the POWERPUFF GIRlS Z!  
Applebloom: i am Blossom!  
sweetie belle: i am Bubble!  
Scootaloo: i am Buttercup!  
Twilight: all of you are very cute! is too bad apple jack and rainbow dash a sick right now!  
Pinkie: dont worry! Rarity and Fluttershy good care them! is too bad rarity dont want go to nightmare night this year!  
Twilight: she a not make her own costume this year and with all the clien she get ,is hard to get time for her! she made the costume of me and cadance in the very last day!  
Cadance: yeah! we both close be missing nightmare night this year!  
Twilight: well let go!  
everypony: Yeah!  
Luna: oh? Sister? is this wonder woman?  
Celestia: yes! i want be with flurry and my sister! let take justice candy flurry!  
Flurry: YEAH! i my first NIGHTMARE NIGHT WITH CELESTIA AND LUNA PLUS THE CMC! YEAH!  
Celestia: we will make it a night to remenber! and we will go to all town in equestria who pass nightmare night!  
Luna: yeah! 16 town! the Crystal empire,canterlot and pony ville is one of them!  
Twilight: wow! we all go to all towns?Ok!  
Cadance: ok! is will be fun!  
Shining: Twilight,Cadance? you really want everypony see dress like this?  
Flash: yeah?  
Twilight: What? we got some hero form DC and MARVAL to Protect us?  
Cadance: yeah! or you dont want it be our hero?  
Shining: Fine!  
Flash: ok! man ,girls can be very controling some time!  
Shining: i know what you feel but is our girls and we want make them happy!  
Flash: this will be a hard night!  
Shining: yeah! collet candy and got sex alter this? wow! this will be a BIG nightmare night!  
Twilight: dont worry! cadance and i , got some magic potion for get gain your lost streng for make more fun!  
Cadance: and we will get our sex time with our hero for a week!  
Flash&Shining: WHAT?  
Twilight&Cadance: we are in heat!  
Shining&Flash: we are DOOM! you really act as demon!  
Twilight&cadance: yes and we are your demon-love! hehehehehe!  
Flash: now i know what is those box in twilight and my room and is the same in your and cadance room!  
Shining:yeah! this will our very HARD CHALLANGE WE EVER FACE!  
Flash: yeah!

@Vocal
 
but Wesker could be a Waifu Thief too..  
can he ?

@Kawa  
Not Flash Sentry the unassuming pony, but Flash Sentry the Waifu Thief.

@Vocal  
But he was already Wesker?

@odiz  
And Flash Sentry as Iron Man.
 

to add to the mix..
 
Spike as Dante  
Shining Armor as Demitri Maximoff  
Flash Sentry as Albert Wesker  
and Pinkie Pie as Felicia

And then they fucked.
 
Twilight’s Brother.