Suddenly Mark's body started to grow, muscles getting bigger and thicker as his face starts to distort into a hellish demon. "A-Aaahhh my body feeLS GREAAAT!" Mark lets out a demonic war, finally transforming into a hulking demon like Ty. He starts stroking himself furiously, shooting thick ropes of demon cum in a quick climax. "Where the fuck is my son?!" Mark shouted in the air, stomping hard on the ground to create a small crater. His demon rage was now taking over his mind, causing all his angry thoughts to become vocal.
Ty gives off a wicked smile and teleports Dustin into the room, already naked and furiously masturbating as the pink mist got to him first.
"I always fucking hated you, you little shit!" Mark yelled at his horny son, his foot long demon cock pulsing hard as it becomes erect. "I wanted a girl, but instead had to deal with your sorry ass!" The hulking demon starts jacking off his cock, making Dustin whimper and moan.
"C-cum all over me, dad! Please!" Dustin begs, letting out a sharp moan as he cums. Mark groans and cums again, shooting thick, demon sperm all over his shameless son. "O-ohh dadd..it smells so good.." Dustin begins licking his father's cum, immediately starting to transform into the opposite gender. Her boobs grew into Double E's, her ass and hips grew thicker as well while her pussy juices started to flood from her nether lips.
Now that Dustin was completely female, nothing was stopping the two hulking demons from having their way with her.