Why do my cooked eggs have a plastic layer on top?

[Archinist]

So, I just noticed after cooking some fried eggs in the microwave, that they appeared to have a tough plastic layer on the top. I removed some of the plastic layer and after cleaning it and washing it, I saw that I could hardly tell the difference from it and real plastic. It did not melt when I put water on it, was hard to chew and tasteless, and was sharp enough to cut my skin. It was hard and snapped into sharp shards when bent enough as well, just like hard plastic shells used in packaging certain products such as toothbrushes or headphones, although much thinner.

Why did the eggs do this? I googled it and found little to nothing. I've never had fried eggs which do this before. The egg underneath the layer still tasted like egg though.