Like the BBC's living spaghetti in the 1960's but in ancient Rome or Athens? But not like the Trojan Horse, I mean a hoax more for fun or to embarass some high ranking person or something.
There is writing from Lucian of Samosata (~150 AD) which details a particular false prophet, Alexander of Abonoteichus. Lucian describes Alexander as something akin to a con artist, using a live snake in conjunction with a puppet to trick Roman people into believing in Glycon, the talking snake god. Lucian goes on to detail each trick Alexander supposedly pulled and explain the method behind it. Lucian was not a fan of Alexander, obviously, and a good deal about what we know of him seems to come from Lucian's writing.
My source is the letter Lucian wrote on Alexander here. I'm not sure if this is what you're looking for, but if you have the time you should check out the letter. It's quite interesting!