Magic Ink
Magic Ink is a tattoo ink you can erase and redraw. Its color comes from photochromic nanoparticles rather than conventional pigment, so a pattern written into the skin with one wavelength of light can be cleared with another and written again, as often as you like.
The ink began as a question in a university laboratory and left as a product. SEAM Lab developed the nanoparticle chemistry; the tattoo artist Keith "Bang Bang" McCurdy, who has tattooed much of the entertainment world, brought the practitioner side; the dermatologist Adarsh Mudgil ran the clinical evaluation of safety and tolerability in human volunteers. Magic Ink reached the market in 2025 (patent pending), and the activation device is protected by U.S. Patent 12,144,953.
The scientific interest is what comes next. An ink that holds a state and can be rewritten is a display, and one that responds to a specific stimulus is a sensor. The same chemistry underlies the lab's work on tattoos that report ultraviolet and gamma exposure from inside the skin.