1 Lambert: Kyros, you’re up. E.
1 Kyros: Ettin.
2 Lambert: Alvissa?
2 Alvissa: This is a silly game!
3 Lambert: No it’s not! Can’t think of a monster starting with F, huh?
4 Alvissa: All right then. Flumph.
4 Kyros: Okay, now it’s a silly game.

The 1st edition of Advanced Dungeons & Dragons was based on a trio of books:

• Monster Manual (published 1977) - a compendium of monsters with descriptions, game statistics, and for most of the monsters, artwork.
• Players Handbook (1978) - a guide for players, with details of character classes, races, equipment, and magic spells.
• Dungeon Masters Guide (1979) - a guide for Dungeon Masters, with information on creating and running adventures and campaigns, creating and running non-player characters, and creating encounters with monsters and treasure hordes, including descriptions of many magic items.

For several years the Monster Manual was the main resource for monsters to use in the game, supplemented by articles in Dragon magazine. Until 1981, when TSR published the Fiend Folio, a collection of monsters drawn mostly from submissions to the UK White Dwarf magazine, with some additions taken from published adventure modules.

While the Monster Manual was a collection of serious monsters drawn from mythology and fantasy fiction, there were several entries in the Fiend Folio that were more unusual, whimsical, strange, or downright silly. Perhaps the most infamous is the flumph. It was so silly that I never used one in any game I ran. Rather than recap in detail the description of a flumph, here's a description and a history of the monster as it evolved from 1st edition to the latest 5th edition.