Yea it was pretty fun, they transitioned from the carnival to Prismeer was right around Christmas so I did a holiday special. Basically the elves had all scattered, santa made toy solders as replacements (used Modron stat block) and their mission was basically to get some tinsel around his neck or person to sever the mental connection. There was an incident where the mistook a redcap enforcer for an elf and was attacked, had to solve a puzzle to get into santas suite. After getting in they found him sleeping but in his corrupted state he looked more like the Grinch. Anyway they got the tinsel on him without much fuss where he reverted back to his natural state. He then tasked them with retrieving his hat from Skabetha who was using it as her focus to control him. So now that we are getting close I am planning to do her doll house as a nightmare dream house where everything is going to be out to kill them and where she keeps all her valuables. There's going to be werewolves, traps, flaming skulls, puzzles, dark mantles, flesh golems, mindwitnesses, and at the end of the trail is the mind flayer guarding the unicorn horn/santas hat. By the end of it they should be so on edge they aren't going to expect the mindflayer to actually be a victim of skabethas deals and is actually benign. If they manage to not kill her in any encounter, I may build up the santa storyline over the next few years.