Secrets of the Mist Stalker
Total Party Kill
Total Party Kill (TPK)
Just what it sounds like. The entire party goes down in the fight with no one left to defend them or recover anyone. This can either mean death, and the start of a new campaign, or it can be a convenient way to relieve your party of some over-powered items by way of having them be captured, and tossed into a prison of some sort.
An unintentional TPK is the holy grail of bad encounter design.
An intentional TPK where actual death results is the hallmark of a spiteful DM.