A machine that can travel through the space-time continuum. Except if you meet yourself in the past, a portal opens up and sucks everything in it. It will only stop if something from the present is thrown into the portal. It is possible to meet yourself in the future, because if you're in the past and you time travel, you'll still be in the present, and if you're in the present, you'll be in the future. There is also a reset button to reset all the time travel that has happened in the day.