Theory: Kingdom of Shrooms' Relation and Influence

Abstract
The mysterious civilization seen throughout Captain Toad: Treasure Tracker is the Kingdom of Shrooms seen in Paper Mario: The Origami King, as well as in Drybake Stadium in Paper Mario: Sticker Star and Shy Guy Bazaar in Mario Kart 7. Subcon was also influenced culturally by this civilization.

Arguments

 * Argument 1: All three civilizations have very similar, Arabian-esque architecture not seen anywhere else in the series, with distinctive domes being the most unique feature. It’s very unique for series standards, and can be seen in locations such as the Shroom City Royal Hotel and Double Cherry Palace.


 * Argument 2: Within Shy Guy Bazaar, there are many connections to Subcon- Cobrats and Shy Guys, species seen in Subcon, inhabit the bazaar, and there is Phanto and Panser imagery on the carpets in the course. There are also flying carpets, seen in Subcon, Shy Guy Bazaar, Flip Panel Footpath, and Double Cherry Spires.


 * Argument 3: Both Subcon and the Treasure Tracker civilization have an emphasis on cherries, with cherries seen all over Subcon and two levels in Treasure Tracker constructed by them containing, and being named after, Double Cherries. In addition, both Subcon and the locations in Treasure Tracker have many Turnips.


 * Argument 4: As established in Mario & Luigi: Dream Team, the Dream World reflects the state of the real world. Taking this in combination with the others, all three civilizations appear to be located within or around the eastern Mushroom Kingdom, specifically Dry Dry Desert and other surrounding areas.


 * Argument 5: Within both Flip Panel Footpath and the Grand Labyrinth, Mummy-Mes, ghostly Toadmummies, can be found. In addition, within the Grand Labyrinth was the Super Crown, a one-of-a-kind artifact with mushroom patterning. In addition, many Golden Mushrooms are found within the Grand Labyrinth. These things suggest a connection to Toads and Mushrooms, one not seen elsewhere within Treasure Tracker.