I put my tea in the microwave this morning then went to sit on the sofa. I heard some crackling noises, similar to the sound that metal makes when in a microwave. I ran over, and hit stop then opened the microwave. The microwave tray was over to one side. I took the mug off but the tray didn't even move. I look and the wheels are still on the spinner. I try to move the tray back and it doesn't budge. The tray was welded to the side of the microwave. :/ So I pried it off and drank my tea. How did this happen? The tray is supposed to be able to resist heating by microwaves. I've seen that metal in a microwave will have electrical arcs shooting into the tray. Was this something similar? Except with such a large current through such a small contact area that the heat caused the welding? I wonder if this effect could be re-produced using more focused microwaves.