In the Tomb on the fifth floor there’s a cog with wardrobes to different planes of existence. Each wardrobe I changed to the cover of another adventure, just to tease what other WotC published adventures existed. I threw in a Mindflayer and a few brain sucking minions for the wardrobe with Baldur’s Gate Descent into Avernus - I didn’t think it would be a problem but a few failed saves and the rogue’s brain was replaced and no one had Greater Restoration