"Well " Sarah began, "I found this great promotion for your cellphone. You sign up to it and they send you these text messages every day. You send these messages to people and it changes them! I sent this one to myself to try it out, and it gave me a pot belly."
"What crap!" Freddie shook his head. "There's no such thing!"
"It's true," Sarah looked disappointed. "I was going to tell you where to get these messages so you could play tricks on your friends and stuff, but since you don't believe me "
"I don't believe you, Sarah! It sounds crazy!"
"Well fine, we'll see how crazy it is!"
Sarah stormed out of her brother's room and went to get her cellphone. It was a good show. She wasn't really upset at Freddie. She didn't blame him for not believing her story because it was crazy. But now she had an excuse to send him every single Mutantext she received, until he apologised. To beg her to stop. And that's what she really wanted, Freddie under her little finger!
Sarah forwarded the message to her brother and lay back on her bed, stroking her belly and waiting to hear his screams