What's he mean by "fake water" here?

Native speaker’s answer
Rebecca
Good question! Actually, "fake water on the ground" isn't meant literally here! He's referring to the phenomenon of mirages, which is when sunny weather creates an optical illusion that makes you think you see water on the road, but there really isn't any water there at all. You might have seen TV shows in which a character is lost in the desert, and suddenly sees an island or lake. This is an example of an optical illusion. You might have seen mirages yourself, when a hot road on a sunny day appears to have water on it.