lolz · interjection, noun1
A corruption of lol, probably a leet variation, treated as if it were a noun rather than an interjection and pluralized in a deliberately unconventional manner using the -z suffix.
LOLZ · interjection2
LOL (Initialism of laughing out loud.) + -z (Eye dialect spelling variant of the plural suffix -s.)
Etymology from Wiktionary, CC BY-SA 4.0.