… you stepped into the beam of a particle accelerator:
Somebody actually did it by accident. In 1978, Russian researcher Anatoli Bugorski performed a high-energy physics version of the old ‘looking into the hose to see why it’s not working’ slapstick staple. Believing that the accelerator at the Institute for High Energy Physics in Protvino was turned off due to a fault, he looked in to check on it – and was hit by a proton beam. His faced swelled up, his skin peeled off and all the nerves on the left side of his face burned away over the course of a few years. However, he survived – albeit with a half-paralysed face and a tendency toward seizures as a memento of his brush with the particle beam.
http://en.wikipedia.org/wiki/Anatoli_Bugorski
What interesting information for a sunday morning!