Based on the image, by Equestria-prevails on Deviantart. Two guards, one Day and one Night, having a drink on their night off.
This more or less came about when I wondered at the backstory of the image, saw several other people doing the same, then decided to make it happen.

There was only one explanation. For all of it. All of the strange, erratic behavior. Her irrational fear of the sun. Her nocturnal habits of locking herself in in the dark and closing all the blinds. Wearing her sunglasses everywhere, even inside! It was time to invest in some silver, garlic, and a wooden stake.

Twilight Sparkle is taken into the nightmare of SCP when containment is breached - can she survive?

Cover Art By: Limey-Boy
Based on the SCP Foundation.

Something I just couldn't get off my mind until I wrote it down. Be warned: the ponies in these battles really go off on each other. Almost exactly like it is in "Epic Rap Battles of History", except with less cursing. There's plenty of verbal bashing, though.

Vinyl Scratch is the DJ for most of these battles, and will be doing the all-caps commentary (except for the ones she's in, of course). OC tag because of slight self-insert.

I've heard that this story is better when read with someone else. You know, with each person doing one half of the rap battle?

List of Rap Battles (as per request)
#1: Twilight Sparkle vs. Rainbow Dash
#2: Pinkie Pie vs. Rarity
#3: Spa Sisters vs. Flim Flam Brothers
#4: Octavia vs. Vinyl Scratch
#5: Angel vs. Gummy
#6: Derpy Hooves (Ditzy Doo?) vs. Lyra Heartstrings
#7: Princess Luna vs. Discord
#8: Scootaloo vs. Pipsqueak
#9: Fluttershy vs. Screwball
#10: Apple Bloom vs. Diamond Tiara
#11: Trixie vs. Featherweight
#12: Silver Spoon vs. Spike
#13: Sweetie Belle vs. Queen Chrysalis
#14: Applejack vs. Carrot Top
#15: Bon-Bon vs. Lyra Heartstrings
#16: Twilight Sparkle vs. Rainbow Dash (rematch!)
#17: Big Macintosh vs. Shining Armor
#18: Iron Will vs. Photo Finish
#19: Gilda vs. Prince Blueblood
#20: Nightmare Moon vs. the Doctor (Doctor Whooves)
#21: Princess Celestia vs. Princess Luna
#22: Snips and Snails vs. Twist and Ruby Pinch
#23: Braeburn vs. Soarin'
#24: Zecora vs. Cheerilee
#25: Winona vs. Opalescence
#26: Derpy Hooves vs. Pinkie Pie
#27: Spitfire vs. Daring Do
#28: Princess Cadence vs. Queen Chrysalis
#29: Babs Seed vs. Lightning Dust
#30: Sunset Shimmer vs. Trixie *
#31: tba

Picture by Silversnow here on this site.

...should there be a 'sex' tag, considering some of the stuff brought up in the rap battles?

Nine humans. Nine Mares. Normal Lives. That's all about to change!

This has nothing to do with Ponyfall. Please, don't confuse our story with that. This is just something we're doing for fun.

This is a collaboration between nine authors:
Marcus: Sartarus
Isaac: Inoeitall
Doug: Gyrofest96
Kasper: Glassed
Coal: Coal Buck
Ryan: RaiderRy4n
Benjamin: The Producer
Camron: Frostbite
Kyle: k12314

In an alternate reality, Discord found his love of chaos came in handy for babysitting young foals. For two thousand years, since he and the princess' were kids, he's babysat nearly everyone in Equestria. Now he's babysitting the cutie mark crusaders, and while he does he recounts with them his many babysitting jobs of your favorite characters as fillies, one by one.

After a long week of suffering, Twilight cannot clear her mind of lingering issues. When she finds Trixie nearly dead, Twilight stirs up feelings for the blue unicorn she didn't know existed. Trixie is all too willing to give this relationship a try, but is Twilight ready for such a commitment? Does she really love this show-mare or is Twilight just feeling guilty over the way she treated her...