The Death Clock was a clever device invented by Professor Farnsworth. When someone placed their finger inside the hole on top, the clock made a sound and printed a small read-out that displayed the future "death-date" for that person. It does however have a margin of error of a few seconds, "What with free will and all...."
Professor Farnsworth intended to present the Death Clock at the annual inventor's convention, but he was forced to make up an invention on the spot when he was informed that he had presented it the previous year.