Have used a pyrex jug to heat water in the Microwave, on many occasions. Leave it "cooking too long, you get exactly the same results as outlined above. It's often possible to take the jug of water out of the oven and place it gently on the work surface...get an ordinary fork and touch the surface....a quite violent eruption can ensue
A half a grape stuck in the microwave on full power will produce a floating ball of Plasma (burning "stuff" ) fascinating to watch, just make sure the Distaff side of the family doesn't catch you.
