"Sure. We just have to figure out what book to use it on..."
"Not so fast young man." The shop owner interrupted suddenly. "I'm sorry. It completely slipped my mind, but though that item looks like a bookmark, it isn't."
"What do you mean?" Jon asked.
"I mean that this item will work on any kind of fiction, not just books. It simply adopts a form appropriate for what it is used on. It was most recently used on a book, and so it has taken the shape of a bookmark. If you used it on a movie or video game, it would appear as something else." The old man explained.
"So we can use it on anything?" Karyn asked excitedly.
"Yes. You can even use it on two entirely different entertainment media at once. A book or movie could be combined, for example."
"That's great! At least if this thing actually works."
"Oh, I guarantee it will. If it doesn't, I'll offer you a full refund." The man said, handing the bookmark to Karyn.
"So, what now?" Jon asked as they stepped out of the shop.
"I think we should..."