The lolocalypse is when something is so incredibly funny, it is capable of exterminating all humans on the planet Earth. Theoretically, the lolocalypse can only occur once, after which all humans will have been killed, and apes with rise to power. This is why it is referred to as 'the' lolocalypse, and not 'a' lolocalypse.
The 'lol' can also be replaced with 'lawl.' This simply make the word easier to annunciate the word.
Prepare yourself for this joke, guys. It could very well bring about the lolocalypse!