Homebrew Minion concept: The Sleeper

My friends are irritatingly good at solving games. So I have been wanting to unleash a powerful minion on them, containing disinformation, madness and a guess to not incure more permanent effects. Inspired by inception, I came up with the following.

For clarification, didn't know what to generally call the storyteller notifications that are unprompted, like cerenovus, character changes or even town info like empathy numbers, I'll just refer to them as Unprompted StoryTeller Information (UDTI)

The sleeper (minion) -each night incept a player with any UDTI ( delivered by the ST of course). At the start of each night the incepted player spins a top and guesses whether they are awake or still dreaming. (Note- awake being the info was genuine, asleep meaning the info came from the sleeper) If they guess wrong they are mad for the rest of the game.

I ran a game with just the 1 night BS info, and no lasting consequences, but it felt weak, and practically pointless. I'm concerned that permanent maddening is too much. And just killing them for wrong guess is too much, but without it, the concept falls flat. Any input would be appreciated.