Getting flames to shoot out the exhaust tips of a car or motorcycle goes back to the beginning of Hot Rodding. Originally flame throwers would just put a spark plug in the exhaust and it would set fire to the non-burnt gas in the exhaust. Creating a flame thrower effect out the back. With modern cars that is much less possible, so people do complete setups with fuel injectors and separate ignition systems just for the flame thrower effect.
Some States do not allow this, as they can be dangerous. Some setups can be done that will shoot flames up to 30 feet away. It does act like a traditional flame thrower and can burn people. So when in use, make sure that you are in an environment that people will not be hurt. Some setups nowadays use propane as a source fuel for the flames. When setting this up in your garage, make sure to use garage cabinets made from metals such as steel and aluminum because wood will burn and plastic will melt when exposed to flames.