World Of Warcraft Classic is introducing Hardcore realms where death is permanent. Blizzard say testing of Hardcore will begin on the Public Test Realm today, June 29th, and have outlined how it'll impact PvP, Battlegrounds, quests and more. In short: they're all being changed to try to stop your death being random or cruel.
Normally in World Of Warcraft, you can run back to your corpse and resurrect if you die. That's no longer possible in Hardcore mode - and resurrection spells and abilities won't work, either. Instead you'll remain as a ghost forever, able to communicate with other players and "resolve logistical matters such as handing over guild leadership", and able to transfer to and resurrect on a non-Hardcore realm, never to return.
To make deaths feel fair and to cut down on potential trolling, WoW Classic will receive a bunch of other tweaks. Players will no longer automatically be flagged for PvP upon attacking another player, for example, to stop players who may "unintentionally take aggressive action against another player who is flagged for PvP, and unwittingly flag themselves." Instead, you'll need to actively type the '/pvp' command to flag yourself manually - although attacking certain NPCs will still apply the flag, too.
Likewise, players will no longer be able to "kite" or lead creatures between zones on Hardcore realms, so as to stop trolls bringing monsters into Stormwind, for example, to kill other unsuspecting players. Instead, creatures will reset back to their starting location upon reaching the permiter of an area or zone.
If you're really keen to throw caution to the wind, players can also challenge others to a "Duel to the Death", a one-on-one fight in which the loser is left dead forever and the winner gets an ear as a trophy. Ick. You can reject the challenge if you don't fancy taking the risk, mind.
It's worth reading the full blog post of changes if you're inclined to play, because there are a lot of little tweaks which seem designed to make your inevitable death as well-mannered as possible. I look forward to reading about the players who just-as-inevitably work out how to circumnavigate the rules just to be jerks.