Will This Ice Sword Slice Through a Watermelon?

If you mix paper or sawdust with water and freeze it, the resulting material — pykrete — is so strong you can forge a sword out of it. That’s just what California-based engineer Allen Pan did. (Pan, you might recall, made Thor’s hammer Mjolnir real with a fingerprint scanner.)

“I’ve wanted to make an ice sword since I was maybe 11 years old,” Pan tells Inverse. He’s taped together cereal boxes into a mold and shaved the edge into an ice blade with a utility knife. He’s also frozen water inside of plastic toy swords. “None of those worked.” Eventually, he stumbled on pykrete, which, thanks to the way the pulp interacts with the ice, is surprisingly tough.

The ice saber was much stronger than even Pan expected. When he swung at the melon, he expected catastrophic failure. “The sword is about 3 and half feet long,” he says. “That’s a huge amount of leverage and stress where the handle meets the blade.” It took about two days of above-freezing temperatures to melt the sword back into wet toilet paper.

His super-chill pop-culture inspiration? “I can’t really remember where I got the idea from in the first place, it was so long ago. But Sub-Zero from Mortal Kombat probably has the coolest looking ice sword that I’ve seen recently.” Slay on.