So I'm designing a dungeon for my group, it's a tower they have to climb as part of a sacred test to reach (they hope) an oracle of some type. The first level is a standard dungeon (rooms traps, etc), then a room of elements (fighting elementals of all four types), a jungle full of plant-type monsters, a maze with minotaurs, and a collapsing scaffold they must climb while fighting gargoyles. What I can't seem to come up with is a final challenge before they reach the top. I thought of having to fight copies or dark reflections of themselves, but that just seems so cliche. Anyone have any ideas? Please help.