Ferrofluid is a liquid packed with microscopic magnetic nanoparticles. Near a magnet, it reshapes itself into sharp spikes that line up with the magnetic field lines, since that shape lets the magnetic pull win over the fluid's own surface tension. Here a rotating magnet drags that spiky peak around the blob's surface in real time. The spike height and sharpness below are driven by the same alignment-and-noise math used to displace every vertex each frame.