Why can a fortune teller burn a coin in his hand?

I have something to say about this problem. I don't know if you met a liar. But coins are hot. I've experienced it myself. I don't believe in ghosts But it may also be related to other things, such as qi. I once suddenly had a hot coin in my trouser pocket, which would burn if I grabbed it with my hand. But nothing around can induce this phenomenon. Mobile phones were not popular at that time, and neither was I. It hasn't happened again until now.