Phone displays are super fragile. And the only way to protect your phone's display is to apply an ugly screen protector on top of it.

But what if you could protect your phone display and make it more scratch-resistant and water-repellent with some seemingly magical goo?

Enter the ProtectPax, an invisible "liquid glass" screen protector that claims it can strengthen any glass.

Currently crowdfunding on Indiegogo, the ProtectPax goo is made of "titanium dioxide nanoparticles, which close the microscopic wells on the glass" and can make your display as "hard as sapphire or ruby."

The company behind it, which goes by the same name, says the liquid-glass nanotechnology was originally developed for use in the aerospace and aviation industries.

Treating your phone's screen seems almost too easy to be true: Just slather the goo all over the glass screen, wait 10 minutes for it to dry, and — voila — you've got a supposedly ultra-tough screen.

The downside? The liquid glass coating is only good for a year before it wears off. My question is, because it's invisible, how the heck do you know if you covered every part of the screen? Also, what are the chances the goo will damage your phone if it seeps into the earpiece of a non water-resistant phone?

Packs of ProtectPax start at $39 for those brave enough to test it out.