You'd have to be a pretty small ninja to wield one of these stars, since they're made of molecules. Or rather, each star is just one single molecule all tied in knots, and they're the most complex molecules (outside of DNA) that we've ever synthesized.
Called pentafoils, these custom-made five-pointed star molecules are comprised of 160 atoms each, with a chlorine ion in the middle. Researchers that the University of Edinburgh figured out a way to make these things more or less assemble themselves from jumbles of carbon chains and iron ions, but it's not just the complex star shape that's so cool: the five chains that make up the pentafoil molecule form a knot, weaving over and under themselves, creating a structure that's both strong and flexible.
Pentafoil itself might be useful as a chlorine detector, but the big news here is that we've now got a way to orchestrate the self-assembly of exceptionally complex man-made molecules, which could lead to the invention of all kinds of brand new synthetic materials with exotic properties. Personally, I'm hoping for some duranium and tritanium so that we can finally start building ourselves some spaceship hulls.