SCIENCE TIME!!!:
The radiation generated from a microwave is infrared (pronounced infra- red) radiation, which is weaker than visible light, which means that it is generally harmless. While this seems like ample reason to stand in front of the microwave to your heart’s content, the only problem is that infrared light excites water molecules and makes them generate heat by bumping into each other. This means that if there was no metal plate on the door to block most of the radiation, you would get cooked by standing in front of the microwave for long enough. Which means that putting a lizard on the microwave would only cause it to cook and it wouldn’t explode. But it would die.