Historically "Trick or Treat" was a deck concept merging Madolche with Ghostrick, using the former to pressure the opponent while slowly accruing advantage, and the latter to stall long enough to get your pieces together. Unfortunately the game has long since sped past this slow accrual of resources. Fortunately, with a dash of new support and a heaping handful of new toys to play with, we can bring back the nostalgic feeling of asking out opponent, "What'll it be; Trick or Treat?"
Madolche is an archtype focused on making rank 4 XYZ monsters, and shuffling cards back from both players graveyards and fields. Mimighoul is an archtype focused on giving your opponent face down monsters, that trigger punishing effects for them when flipped face up. There doesn't seem to be a whole lot of synergy on the surface, but there are a few advantages to mixing the two. Firstly, both of these archetypes are comprised entirely of Earth monsters, making the Vernusylphs an easy inclusion, especially with their ability to access strong starters for Madolche. Second, the Mimighoul cards cover a lot of Madolche's weaknesses. The Madolche cards have a lot of powerful normal summons to access their combos, but lose to pretty much any interaction on them. The Mimighoul cards can threaten searches and summons without commiting the normal summon, and often without putting monsters in the GY to leave madolche open to take over from there. Even less impactful Mimighouls like Armor or Cerberus can insulate from many popular hand traps like the Mulcharmmies and Imperm by placing a monster on the opponent's field, and with the newest wave of support, any spare bodies left behind by the Ghouls can be funnelled into Meowcaroons to find full madolche combo regardless of the madolche name you open. Also, running this many engine cards is a great excuse to play more than the minimum 40, which reduces your odds of drawing the brickier cards in each archetype by diluting your deck with more searchers and starters.
There are a couple of issues to keep in mind with this list. 1) less non-engine. Fitting 3 archetypes into 1 deck sounds great until you really really really need to see a board breaker or a hand trap or SOMETHING to interrupt your opponent, Unfortunately this is a duel, not a game of solitaire. 2) Nibiru and droll. None of these archtypes play super effectively into either of these cards, and the more searchers and extenders your open, the harder you play into them.
With that I hope you have fun playing this concoction of confection and confusion, and a happy Halloween!