Okay, so it's not a real lightsaber - but it's a darn sight cooler (and more deadly) than that plastic telescopic job you got "for your nephew" a few years back.
The creation of electrical engineer Allen Pan (who made a 'real' hammer of Thor a few months ago), this lightsaber is actually a homemade micro flamethrower - ejecting a burning stream of methanol and acetone fuel from the handle of a lightsaber prop.
Pan modified the lightsaber handle by inserting a 3D-printed syringe valve, capable of ejecting a constant stream of fuel that burns at a set length. By hitting the soundeffect button, the saber emits a stream of the burning fuel - not unlike that eyebrow-ruining trick you learnt at school with a Lynx can and a lighter. By mixing different chemicals, Pan was able to give the "blade" a coloured glow.
Sure, it can't cut through solid steel, but it still does plenty of damage to an effigy of the most hated alien in the Star Wars cannon.
As soon as scientists have figured out how to harness the power of light to create a physical cutting beam, we'll let you know.