Generra's infamous thermochromic Hypercolor t-shirts were designed to change colors according to the wearer's body temperature. For a season or two, these were must haves -- until word got out that hot water washes and over-drying destroyed the shirt's aforementioned thermochromic properties. Generra was forced to stop producing Hypercolor altogether after losing a class action suit, filed by unlucky Japanese who discovered that the underwear had permanently Hypercolored the skin underneath.