When Jessica through the medallion at him Jake caught it instinctively and said "Shit" as he realised he still had the collar in hand which he tried to drop but was too late as he felt the shock of the medallion working.
"What did you do that for" he yelled.
"As I said you are now acting as the bigger ass-hole" she said.
At that moment Jessica could see the transformation start, but instead of turning into a dog Jake was turning into a girl.
As Jessica watched Jake's hair became a dark black, he shrank to a 5'-4" and he was becoming quit the looker. It was when his breasts grew to a D-cup and his face finished changing that Jessica recognised that he had become that punk bitch Marcy.
When the change had finished Jake had grabbed her new large breasts before diving for the medallion again to change but could not figure out why it was not working.