u/sonixos

Good day to all DMs out there i came here in my time of need i been working on a dungeon for bit now and im kinda stuck. i wanted to create preaty big dungeon that would involve maze some puzles and a dungeon crawl at the end, but i am stuck at the moment on the last puzle since i dont want to make i easy on them (the setting of the dungeon is blood cult hideout) any ideas ?