There's a small trick I sometimes do in class involving my chair. It's not particularly impressive but my students seem surprised and laugh when I do it and of course try to imitate it. It's a bit noisy and one day a very cheeky girl in one class said I had to do it without making a noise. I tried but couldn't - it's impossible. She then said I had to do it next week.
Next week came (Friday) and I tried again and failed. Cue the torrent of abuse from two very cheeky girls.
"You are lie man!"
"You are no promise man!"
"You are 거짓말쟁이" - liar
"You are Pinocchio!"
They then put rolled up their notebooks and put them to their noses and continued to call me Pinocchio for the rest of the class. Cheeky kids but funny times.