I'm pretty sure it's this one
when rs2 turned in to EOC and there was no OSRS so everyone moved to battlescape, and there was a 3v3 fullout where each clan was able to pull 100+ and there were also main and zerker clans crashing with huge pulls too. The whole fight lasted for hours and had probably over a thousand people fighting. I know it's not actually runescape or osrs but at the time that was the only option for runescape and a few clans in the video are still around in osrs today.
I eat rocks got a reaction from Ace Krave in Biggest pure clan fight?
I eat rocks got a reaction from Tictac in [ARCHIVED] Edited Plawpy's Sig.