It's something to do with defense mechanism, intestine disorder or build-up of natural gases created by bacteria so they start to expand until the pressure is way too much and they explode! Explosions of toads in attempt to look bigger when attacked by crows in Germany, self detonating ants to protect their nests from intruders in Asia, deers, sheep...
R laughed at me when I tried to tell him about this phenomenon and it triggered me to wonder if humans can explode naturally too. I told R I wanted him to explode when he laughed at my English.
With the way he is stuffing his face now, I hope he explodes. HA!!!