Make a dungeon plugin where players can buy or just get dungeons by doing /dungeon [tier] and then the plugin spawns a dungeon away from the map in the air and teleports the player there and the dungeon has npcs and maybe even some wolves or sm and then when they get to the end there will be a bit stronger boss npc and when they defeat them then they can enter a portal and get teleported to their last location they were at when using the command