Ferrofluids — oily substances filled with tiny particles that respond to magnetism — have been around for decades, and now they’re actually becoming useful. Airlines use ferrofluids to help seal rotary valves. Loudspeaker manufacturers use them to make better speakers.

But mostly, ferrofluids are used to creep the living heck out of people. That’s because when you bring a magnet near a few drops of this stuff, it writhes like some sort of silicon-based alien substance that is about to COME TO LIFE AND CRAWL UP YOUR NOSTRILS AND KILL YOU.

Don’t believe me? Check out these videos on this page. In particular, dig this one where a bunch of ferrofluids pick up a penny and move it around. Yeeee.

(Thanks to El Rey for finding this one!)