Believe it or not? This pen uses heat to erase ink. Engineers Jack and Patrick Aubin wanted to be able to erase ink without smudging. Their HeatVanish pens use heat-sensitive ink that disappears. Leaving a clean space behind.
Don’t worry, the pen automatically shuts off after 15 seconds. Its cap covers the switch so it won’t turn on in your pocket. It sells for $35 on Kickstarter.