The Abandoned Warehouse

It was the year 1960. A group of three women and three men made their way to an abandoned building on the West side of town. Here, they performed the darkest of practices: Satanic worship. They performed dark rituals and opened up a portal to the other side. They drew horrific things on the walls and wrote their names in blood. Each member of the group was found guilty of other crimes and sentenced to life in prison, never to see the outside world or praise their dark leader again.
It's now fifty years later and the story of the abandoned building has been passed down through generations. It's Friday the thirteenth and a group of three girls: Mandy, Jess and Tori; and three boys: Eric, Dylan and John; decide to go to the abandoned building to awaken the spirits that reside there. The six teenagers arrived at the building. "You guys ready for this?" asked Eric.
"Ready than we'll ever be." answered Jess.
They approached the door but no one wanted to go first. They all looked around at each other frantically. "Oh, fine. I'll go first." Dylan finally said. He pushed open the door and entered with the others following behind him. They walked through the dark halls until they reached the decomposing stair case. The stairs creaked as they made their way up them to the second floor. They slowly walked down the hall to the last room on the left.
"This is it!" John whispered. Mandy walked around the perimeter of the room, gliding her hand against the cold brick wall, touching every picture that was painted on. The six kids sat in a circle in the middle of the room. They waited and waited for something, anything, to happen. At about three in the morning, strange things began to occur.
"Ouch! Guys! I feel like my arm is on fire! What's going on?!" Dylan shouted. Tori flashed her light onto his forearm and saw three distinct scratches put there by an unseen entity. About twenty minutes later, they heard a shriek. Jess turned around to see Mandy being picked up off the ground by her hair and thrown eight feet across the room. They heard a dark, evil laugh and Tori ran over to Mandy trying to help her get up. The back of her head had been cracked open and was dripping blood. Tori felt a hand grasp her ankle and she was dragged across the floor to where the portal had supposedly been opened. She began to feel dizzy and the room started to spin.
“Hey, why is the room spinning? I feel kind of funny…” Tori began to say until all of a sudden, her body was contorted and jerked about violently. She was possessed.
“We have to get out of here!” Eric yelled. Dylan picked Mandy’s limp body off the dirty floor and Jess grabbed Tori by the arm. They managed to make their way out of the abandoned warehouse and back out to the street. The six of them ran as fast as they could in no particular direction; as long as they were away from the haunted building. The next morning, a construction crew went to the building. They boarded up the windows and marked it off with caution tape so that no one could enter into the room that contained the portal to the fiery depths of Hell.