Want to disappear? A new invisibility cloak offers you the chance — provided you carry around a portable fog machine.

The cloak, described June 5 in Science, achieves the challenging feat of hiding an object from all angles and all colors of visible light, with the caveat that it works only in hazy environments including clouds, fog and frosted glass. “It’s a nice demonstration,” says Jason Valentine, a mechanical engineer at Vanderbilt University in Nashville. “It sacrifices functionality in one area to gain functionality in another” — namely, the disappearance of the object to the naked eye.