Sharing with the sitter

"A wish-granting rock?" said Sheila. "But that would have to be magic!" "Well, how else could I turn you into a monkey?" said Mikey. "That's true. Show me this rock." "It's in Jon's room. I'm supposed to stay out of it." "Well, you went in already today. Another time won't hurt. And I won't tell, I promise." "Well -- okay." A few minutes later, Mikey and Sheila were in Jon's room, looking at the rock. "Wow," said Sheila. "Can I see it?" "What for?" asked Mikey, suddenly suspicious. "I just wanna see it! Please?"