Careful when playing the games at the Delphi Carnival, you might just get tricked. Just kidding! You can get a trick or treat item from 2018 or before by: picking a red or blue mallarchy in Mallarchy Pond, winning a game of Ring Toss, popping a balloon with something in it at the Balloon Hunt, and if you win a certain amount of tickets in a game of Bluff.
Good luck, my spooky loving pals.
Gave up on the balloons since it costs 3 tokens and the others only cost 1, but will keep trying the others.