Costume Kingdom

You'll earn this trophy when you've completed the third and final Apex. The portal to the Apex is located on the North side of the map (inside the Cypher HQ) and will cost 1,350 candies to open. You want all of your Hallowmon to be Level 20 before going into this Arena. Even if they're not your main, it's best to just max them out as it'll make it far easier and will also better prep you for the fight required for The choice. Make sure you have all possible Quests completed as this will only aid in leveling up your Hallowmon. The Quests you should have left to do (after Apex 2) are the following:

• I like turtles
• The Hallowzoo

You should also have enough candies to open up the exhibits for Collector so go ahead and get that done before doing the 3rd Apex as well.

After a handful of Goon fights, you'll go up against Pineapple, the reigning Champion of the third Apex. Once you defeat him, interact with the portal just after where the battle took place and you'll unlock this trophy. You'll also earn the Magmos Costume/Hallowmon. You can also pick up the Chickolix Costume/Hallowmon just to the right of the Apex portal (down the stairs). It will be in a chest.