Can you actually blow up a microwave with metal or... is that a myth?

I'm gonna start off by saying.. Several times as a child I accidentally put these metal bowls we had, alongside with forks and spoons, in the microwave. A lot of times they went for long stretches of time in there while I would heat up my food, only to be removed by my Mom since I would often run off into the other room to play, not hearing the popping and sparking.

I've read plenty of articles about what kinds of metal can go in microwaves, but I've seen none about if metal can actually cause harm or go so far to blow one up.

My point is, with all those incidents, I would have thought I would have ruined a microwave by now. Is it just a hoax? Does metal just spark a little? Or can you blow up a microwave by leaving metal in it?