Wikipedia
Hypercolor was a line of clothing, mainly T-shirts and shorts, that changed color with heat. They were manufactured by Generra (now a division of Public Clothing Company) and marketed in the United States as Generra Hypercolor or Generra Hypergrafix and outside the US as Global Hypercolor. They contained a thermochromic (temperature sensitive) pigment made by Matsui Shikiso Chemical of Japan, that changed between two colors–one when cold, one when warm. The shirts were produced with several color change choices from the late 1980s until the early 1990s. Unfortunately the effect could easily be permanently damaged, particularly when the clothing was placed in a hotter than recommended wash.