I had an idea the other night
In some Paper Mario games, there's an optional dungeon called the
Pit of 100 Trials. My idea was that there is a spawn and lobby where people can buy weapons and healing items for points, along with forming parties with other players. Once a player has equipped a loadout, they can choose to enter the dungeon. Once they enter, they are trapped and cannot leave unless they get to an intermediary point, beat the dungeon, or die. Every room will be harder than the last, with the first room, say, having a 40hp knight with a stuff sword, the second having two stuff knights, third having a small bear, etc., escalating up to a pit boss with high health and damage (say, a large 1500hp dragon or T-Rex with a Pixel Bomb spell) that gives large amounts of points when killed, and maybe even some sweet loot. Intermediary floors would have a reward (say, some alright loot and ~25 points), and an exit if the player wants to leave. Room exits would only open up once the baddies are defeated, and they would be a one-way trip to the next room. Each room would give a point when cleared, maybe more for later, harder rooms. To keep players from bumping into each other, you could dup the dungeon a few times and make monsters spawn in only when players enter a zone in the dungeon
