All these years I had always thought it fruit they gave Vaal. Which I thought was dumb because he generated HUGE amounts of energy from it apparently! But now, the exploding rocks make more sense. There is probably a cut scene somewhere that explains it all.
I have to say, ``Now the exploding rocks make more sense'' was not a sentence I expected to read when I woke up today.
However, yes, Vaal being fed exploding rocks does
make a good bit of sense, so far as that goes.