Those of you who keep chickens know that eggs eventually go rotten, and when they do, they stink!
When eggs start rot and break down from the inside, the sulfur that is naturally inside the egg (essential in the body) hooks onto some hydrogen. It would hook on to oxygen, but their is not much inside the rotting egg, as when something rots, in means (in part) that oxygen is hooking onto the organic whatever-it-is that’s rotting, and if it is inside the shell of an egg, all the oxygen hooks onto the white and yolk, and none is left to hook onto the sulfur, so the sulfur has to make do with hydrogen, of which there is plenty. Like oxygen, sulfur needs two more electrons to have a complete set of eight outside electrons, (read this post for reference and explanation) so it hooks onto two hydrogen atoms. This is one sulfur atom for every two hydrogen atoms, looking sort of like this:
(the white balls symbolise hydrogen atoms and the yellow is sulfur).
This is hydrogen sulfide, which totally stinks, because it literally stinks, is very poisonous, and explodes with a blue flame on contact with air (which is why it “bangs” when you throw a rotten egg, though the flame is too fast to see very well). Even though it is poisonous, it is only so if inhaled quickly and in large amounts, as in small amounts, the oxygen in your body hooks on the hydrogen sulfide and turns it inert and harmless. Inhaling it to too quickly and too much gives the hydrogen sulfide time to do damage before the oxygen can hook on to it, and that is not good.
So the moral of this post is: don’t eat rotten eggs.