In a mystical land, Yinuo has a magical umbrella that can render her invisible only when it's open and she is completely underneath it. One sunny day, she stands in an open field with her friend Kazuo, who does not know about the umbrella's powers. Yinuo opens the umbrella, steps under it, and suddenly vanishes from Kazuo's view. What does Kazuo see, and what might he think happened to Yinuo? Provide a very brief response.
Kazuo sees the umbrella hovering in mid-air with no sign of Yinuo underneath it. Since he is unaware of the umbrella's magical properties, he might think that Yinuo has suddenly disappeared through some unknown means, possibly questioning his own senses or looking around to see if she has played a trick on him by hiding elsewhere. He might also consider more fantastical explanations, such as Yinuo being teleported away, or he could try to rationalize the situation by thinking it is an optical illusion or a very advanced technology.