Sheer Mountain Range is a Mystery Dungeon in Pokemon Super Mystery Dungeon. It is the first of two dungeons you visit after leaving Serene Village to go to Lively Town. Poyo Ride had some troubles with this dungeon, one time even forgetting apples while he had all the other sexy items, which he lost. Poyo put this dungeon into TARS as a stupid ass mountain you cannot get past.
The dungeon where every stinkin enemy is a Genesect is easier than this.