It looks like it’s alive, perhaps like a spider or a slug, but this is a ferrofluid! Ferrofluids are a magnetized liquid that gets pulled this way and that by nearby magnetic fields.
Here a ferrofluid has been submerged in a clear alcohol-based solution in a shallow dish while a permanent magnet is used to perturb the liquid. Instead of forming its distinctive spikes due to the normal-field instability, the fluid forms ribbons and mazes due to the shifting magnetic field and the surrounding fluid.
via ahem, f—-yeahfluiddynamics.