A man left a Lava lamp left on hot stovetop and it exploded. the authorities are wondering

Why on earth he was heating a lava lamp on the stove

I can tell you why. Lava lamps are only really cool when the wax inside is warm--they get the cool rising blobby effect. This is usually done by the bulb that is inside the lamp, but it takes a while for the lamp to reach a point where it is warm enough for the cool effect. I have a feeling he was trying to accellerate the process. I am curious as to what, exactly, caused it to explode.