Despite the fact that Mark still knew he was Mark, he now felt this strange compulsion to be a middle-school girl. He knew it was just an effect of the device, switching his personality with that of his thirteen year old sister. And yet, it now seemed the most logical thing in the world to go and switch bodies with her now as well... making her the new Mark and him the new Heidi.
He quickly went off to find Heidi.
He discovered her sitting at the breakfast table, hungrily shoveling food into her mouth.
Gross, thought Mark. She eats just like a boy! What a disgusting slob.
In fact, Mark noted she had already spilled some food the pretty pink sweater she was wearing. That clinched it, for Mark. He felt envious of Heidi's pretty clothes... and felt angry that she didn't even care about them enough to avoid spilling food all over them!
Mark quickly aimed the device at Heidi, hit the Body Swap button, then aimed it back at himself and pressed the button a second time.