The -Minus World hallucinated a ransom demand from Bowser to Mario Re: Princess Peach (aka "ho" according to this) — but look closely. All the letters were cut from game-related logos.
Can you guess from which source all 39 letters came? Skimming over it I can recognise a dozen, easily. Spoilers are in the comments at the link.
Mario Receives Ransom Letter [The -Minus World]