Old School Runescape went offline for several hours earlier today, after players discovered an issue that let them crash the game via a 14-year-old tradition.
Earlier today, OSRS got an update with some relatively small technical changes. Shortly after the update went live, players began to realize that sending rainbow text through the in-game chat would crash the game - not just for themselves, but for anybody in range to see that text. That's something that could pretty easily be exploited by unscrupulous players looking to get others killed.
Developer Jagex initially described a "report of one player being disconnected due to a crash during the Zebak fight," but it quickly became clear that this was a much wider potential exploit affecting anyone using the Java OSRS client. Within a few hours, the devs had taken the entire game offline to fix the issue, and while everything's back to normal now, players spent the intervening time dragging OSRS's propensity for introducing game-breaking problems with new updates.
While 'entering particular things into text chat in order to crash the game for yourself and others' might sound like something far too specific to have happened more than once in an MMO's lifetime, there's actually a similar 14-year-old incident so infamous that it has its own page on the Runescape Wiki. Back on February 25, 2009, players started crashing the game by typing the 'µ' character into text chat. Old bugs die hard, it seems.
At least nobody is pouring "hot coffee on his butthole" in this particular OSRS incident.