Historical reminders of Knightmare

[Drassil]

In passage 61 of The Quest for the Dragon's Egg (a.k.a. the gamebook section of The Forbidden Gate), Pickle remarks that a large pineapple "Looks like a hand grenade" then adds "At least, it will do once hand grenades have been invented" when 'he remembers that Knightmare Castle exists in medieval times.'

However, there is evidence of grenade-like projectiles being used at the time of the Crusades. This post in The History Blog has details.