YMMV / The Museum

• Captain Obvious Reveal: The Abyssal Sanctuary is full of Clowns. Not exactly helped by the way the front page gives it away post-exploration by adventurers.
• Demonic Spiders: Night Trolls, for lower-level adventurers. They're Lightning Bruisers with naturally high combat skills, can easily perma-cripple limbs with their bite-and-shake attack, almost exclusively appear in as wandering units on the map (so they can very easily ambush you), and are very widespread in the northern areas of the map.
• Good Bad Bugs: Kosoth Griffonblaze somehow managed to bypass the legendary+5 skill cap, presumably via one of these.
• I Knew It!: Lurker Z theorised that Bralbaard (the GM) unretiring Bralbaard (the adventurer) would lose him his kingship. This proved correct as of Turn 61, where Bralbaard’s unretirement saw him lose the position of Walled Dye monarch. He also noted Moldath was still part of The Armors of Diamond even as he was retired in the other dwarven civilization (The Staff of Kissing) and theorised this would have an effect on the character’s movements; in-game years later, Moldath (now an NPC) returns to Clearmasters without a care in the world.
• Memetic Badass: Dishmab Northmanor the Mute Saffron Soot earned this reputation in the first Museum game, due to being a functionally invulnerable, ludicrously high-skilled badass who could easily take out almost anything in the game in battle. He (and his creator, Kesperan) are unofficially considered to have "won" adventure mode as a consequence.