In this video, artist Afiq Omar mixes ferrofluid with soap, alcohol, milk, and other liquids to create a surrealistic fluidic dance. In addition to using different fluid mixtures, I suspect he accomplishes many effects using several different permanent magnets and electromagnets to vary the magnetic fields around the ferrofluid mixtures. (Video credit: Afiq Omar; via Wired)
This image shows a ferrofluid - a liquid that is magnetic. It consists of nanometer-sized maghemite particles dispersed in a liquid. Maghemite is γ-Fe2O3, a kind of rust.
The maghemite is put on a watch glass, with a magnet placed under it. The so-called spikes point in the direction of the magnetic field of the magnet.