Jack was mixed between pain and pleasure as brown fur began to sprout on his face. His nose began turning black and pushing out into a mussle as his ears reshaped, grew fur, and moved up on his now very lupine like head. This was all happening before your eyes as he came inside your body. As he continued humping away, the changes continuing on his head, black fur began to sprout on your face as well. Soon you began to go through similar changes as Jack. This was all happening so fast that as you began to feel your changing face with your paws, you began to freak out. You pushed Jack over so that now you were on top and tried to pull off of him. You couldn't pull off though, feeling his huge swollen knot inside you, you knew it whould be some time before you two could separeate.
Taking several long deep breaths, you begin to calm down. "Dude, what the fuck just happened to us?!" you ask.
"I'm not totally sure," Jake pants. "It's like we became the wolves from the costumes!"
"But how?"
"Fuck, I don't know! Maybe that's what they were supposed to do!"
There is a long silence as you lie down on Jack's stomach and begin to fall asleep. Soon Jack yawns and begins to sleep as well, his cock still embeded in you, his knot still engorged... When you wake up...