Randofo published the details on this flamethrowing Jack-O’-Lantern on Instructables. This bad boy is designed for remote control via Squidbee RF modules so you can shoot a one-second burst of flame on command. (As randofo observes, you should be able to substitute any Arduino/XBee combo for the SquidBee.)
This definitely qualifies as a Dangerous (Halloween) Prototype!
Get all the build details and the Arduino sketch at Instructables.
Happy Halloween!