Like some of your finer cheeses, Silly String comes in an aerosol container and can be sprayed at targets up to 10 feet away. Sadly, it’s not edible. Or is it? Its container tells us that Silly String is non-toxic and non-flammable, two prerequisites for most foodstuffs. It’s supposedly free of chlorofluorocarbons—archenemies of the ozone layer—but the dreaded CFCs have been found in the propellant inside some Silly String cans. Let your conscience be your guide.

Silly String is definitely not edible. But what is it? Its chemical formula (or DNA, it might be alive) is a proprietary secret; it could be made from precious moonstones for all we know. When you depress the spray nozzle a long, foamy string of silly shoots out; at first it’s cold and a little liquid but soon solidifies into plasticized cords. Silly String hit the shelves in 1969 and became a popular item in novelty and party stores. Pranksters everywhere pretended to sneeze and sprayed innocent bystanders with brightly colored string. For an excellent how-to demonstration, see the movie Big with Tom Hanks.

There have also been detractors leading the fight to rid the world of Silly String. Many towns have banned the foamy goodness and the EPA has handed out stiff fines to companies importing Silly String cans that use CFCs as propellant. As nifty as it is to have string fights with your friends, the long sticky ropes are hard to clean up and can clog municipal drains. It has also been shown to stain vinyl and while the fully-solidified strings are somewhat fireproof, Silly String just coming out of the nozzle is very combustible.

If you no longer use Silly String out of fear for the depleted ozone layer but really yearn for snot-like strings being propelled through the air, take heart: if science has taught us anything, it’s that weird, gooey toys get invented in industrial labs all the time (by accident).