Brusspup, one of YouTube’s top scientists, has returned to debut an Incredible Chemical Reaction that seems to border on magic.

After dissolving sodium sulfate and citric acid, and sodium iodate in two separate cups of water, the host mixes the two and in just a matter of seconds, the perfectly clear water turns pitch black instantaneously. The reaction is actually well known in the chemistry world, and is more commonly called the iodine clock reaction.