Has anyone else tried else yet? One of the guys at the firehall put one in my boot but I saw it before I stepped on it.
You simply crush it then walk away, after about 2 mins the bag will explode and stink. Very handy for screwing over your friends, only 50 cents each at most 7/11s.
They are small enough to fit though a cracked car window so I bought a few to keep in my glovebox.