I have seen the custom of bothering the chazzan during the musaf service on Simchas Torah. I have seen people tie the chazzan's gartel to a chair, or try to move the chazzan to a diffrent place. I even heard that in one shul they threw the chazzan into the mikvah!
What is the source and when did it start? It seems from a halachic standpoint that is 100% assur to do so (see Hilchos Teffilah in Shulcahn Aruch and Aruch Hashulchan about how one should act for davening).