Blood Runes

Twilight, Raaity, Fluttershy, and Apple Jack all raced into Ponyville's nut house, as a psychiatrist had said they were needed there at once. The four were given directions at the reception desk and trotted to the room the three demented mares were in.

At the room they saw about ten guards, four psychiatrists, and two police ponys in the hall in front of the room, looking through a large window. The 16 ponys by the window let the mares look through, not prepared for what they find.

"Is that Pinkie Pie and Rainbow Dash?!" Twilight practically yelled after looking through the window.

Blood Rune tried to break free, but the chains were magically reinforced.

"Heheheheheheheheh" she giggled in an uncontrollable manner. "MWAHAHAHAHAHAHAHAHAHAHA! HAHAHAHAHAHAHHAHAHAHAHA! HAHAHAHAHAHAHAHAHAHAHAHHAHAHAHAHAHAHAHAH!"

Soon all three of them were laughing like the madmares they were. one of the guards pressed a button, tazeing them all. As the caged ponys fell to the floor, twitching, but knocked out, the four free mares noticed something they had always passed as unimportant. Faint red stains. The ponys quickly realized that these had developed over years of continuous murder.