My favorite part of the Monster Manual are the bits of in-character/in-game lore that are notes on the pages.
- The Far Realm: Real Yet Unreal by Vaqur Zekh’r
- Hooves of Fury by Irvil Grayborn of Sandown
- Demonicon of Iggwilv
- Mordenkainen the Archmage’s Chronicle
- Manual of Clay Golems
- Diary of Evangeliza Lavain, necromancer
- Night of the Kraken Cult by Malfeore Serrang, Pirate-Mage of Tethyr
- Journal of Jaster Hallowquill
- Sonnet of a Naughty Satyr (scroll)
- Tale of a Half-Orc Ranger
- Masters of the Forbidden City by Codo Vidak
- X The Mystic’s Rules of Dungeon Survival (series of scrolls)
Ah, X The Mystic’s Rules of Dungeon Survival!
X The Mystic’s 1st Rule of Dungeon Survival: Trust a Flumph.
X The Mystic’s 2nd Rule of Dungeon Survival: ?
X The Mystic’s 3rd Rule of Dungeon Survival: Sometimes a chest is just a chest, but don’t bet on it.
X The Mystic’s 4th Rule of Dungeon Survival: No one carves statues of frightened warriors. If you see one, keep your eyes closed and your ears open.
X The Mystic’s 5th Rule of Dungeon Survival: ?
X The Mystic’s 6th Rule of Dungeon Survival: Keep a few gems in your pocket. A hungry xorn is a helpful xorn.
X The Mystic’s 7th Rule of Dungeon Survival: Before opening a sarcophagus, light a torch.
If you possess any copies of X The Mystic’s scrolls containing any of the lost rules, please present them to a librarian, so that their authenticity can be ascertained and then transcribed.
If you would like to get an email notification when blog posts are published, please subscribe below:
Githyanki Diaspora 
I do believe that X the Mystic’s second rule goes as such, on the topic of water weirds:
“Before you drink from a fountain or pool, toss a copper coin into it. It’s a small price to pay for your life.”
https://dorod.obsidianportal.com/wikis/x-the-mystics-rules-of-dungeon-survival
It’s all here.
X the Mystic’s Rules of Dungeon Survival
1. “Trust a Flumph.”
2. “Before you drink from a fountain or pool, toss a copper coin into it. It’s a small price to pay for your life.”
3. “Sometimes a chest is just a chest, but don’t bet on it.”
4. “No one carves statues of frightened warriors. If you see one keep your eyes closed and you ears open”
5. unknown
6. “Keep a few gems in your pocket. A hungry Xorn is a helpful Xorn.”
7. “Before opening a sarcophagus, light a torch.”
my rules that i have compiled