Jon looked down at himself and saw that he was in his mother's body! It must have been a body swap that happened.
"Oh my god, what happened to me?!" he heard his voice yell. He looked up and saw himself standing just a few feet away. The facial expression was pure horror and confusion.
"Mom, listen to me. It's okay," Jon said. It was so weird hearing his mom's voice when he spoke.
"Jon, tell me what's going on," she said, settling down, but still clearly freaked out.
Jon didn't bother giving her (or was it him now?) an explanation. He (or rather she) reached out and touched Jane's newly-acquired hand and said "Swap."