@futurebird stupid question. You need to charge your food (or Hamster) before heating it. Cold food (or Hamsters) are known to be low in energy, as the calories are not active in a cold state, so you'll have to charge it Up. As an alternative you can also put a (at least 5000 mAh) fully charged Li-Ion battery into the microwave. Works basically the Same. You're Welcome.

Oh, and just to be on the safe side: if your house burns down, it must've been because you didnt use USB 3.0 or the battery wasn't fully charged.