So far, I've clicked on "Treat" for:
- some candy, and a small sack containing 5 shiny gold pieces.
- some candy, a feybread biscuit, a feybread biscuit, a restful bedroll, and a potion of vitality.
- some candy, a ring of protection +1, a ring of protection +1, a ring of spell storing (greater), and a potion of life.
- some candy, an endless canteen, astral mead, and a goodnight tincture.
- some candy, a banquet ring, a potion of cure light wounds, and a set of deluxe core rulebooks.
- some candy, 7 bottles of fine wine, a banquet ring, and a level 30 treasure parcel.
Clearly, monsters in some dungeons are more generous with treats than the ones in the dungeon next door.
As for clicking "Trick", that's given me:
- a rotten apple, a rusty nail, and an old shoe.
- a rotten apple, a small sack containing a single tarnished copper piece, and cave slime.
- a rotten apple, a set of thieves' tools, and a twig.
- a rotten apple, a moldy slice of bread, a leaky waterskin, and a blinding bomb.
- a rotten apple, a small bag of candy corn, a flask of acid, and cave slime.
Looks like candy corn is considered a trick, not a treat.
Nice to know somebody at WotC still has a sense of humor. Be careful of clicking the falling leaves if you try it, BTW: they're random links.