Shortly after the Super Soaker was first released in 1990, it became surrounded with controversy about hooligans allegedly filling the toy with harmful chemicals. But if that sounds dangerous, just imagine how local news stations would freak out over a squirt gun that blasts molten liquid metal.
Kevin Kohler — aka the Backyard Scientist — used pewter, a malleable metal with a low melting point, to fill his custom-built squirt gun. Those lower temperatures mean his invention is a little safer to use than you might initially assume — but not by much. Watching it slice through a pewter pitcher like a high-powered laser is satisfying, but this is the last thing you'd want to use to cool down on a hot summer's day.