Oh, I know, talk about how they're all an illusion because it's all in your head and none of them really exist because you made them up. That should creep them out- my old maths teacher used to do it to us.
Why don't you do something which is of great interest to you? . . .ie hobby . .
When I had this same sorta thing at college many moons ago, I did my presentation on Dancing, as that means a lot to me, ie hobby since I was 4 years old.
I found doing this, I was comfortable talking to my audience and I knew what I was talking about. I also bought in my Pointe shoes as a visaul aid as the people in my class had never seen a pair of Pointe shoes, really did get the class gripped on what I was talking about.