Cloak of Invisibility

"I think I'll try this," Jon said, walking over to a black cape and picking it up. On the slip of paper resting beside it, there was a brief description of the object. It was the Cloak of Invisibility. The instructions were as follows: Simply put on the cape and you will become invisible. WARNING: Make sure you do not use any other magic or magical items while cloaked. Results are unpredictable. Jon put the wishing stone back in the box that it came in. Perhaps using magic during invisibility caused a trivial mishap, or perhaps the outcome would be more catastrophic. He didn't want to tempt fate. He held up the black cape and put it on. Immediately, his reflection in is bedroom mirror vanished. "Cool," he said, then wondered how he should use his new "ability".