#1. Make begging a real trick or treat. Option for 1 of the enviromental items in the game. Not the same rare web over and over. Or something like that.
Think about it, a shop keeper can give 1 of a 1000 things.
#2. Random black cats in the realm. If you attack them some random spawn occurs. Maybe easy for 1 player maybe the need for 3 players. Rewards of some sort. Maybe colored caldrons.
#3. I heard a halloween ship wrecked along the coast. Fishing anyone, I hear some loot was picked up by monsters along the shore.
#4 Odd stuff is showing up in the cavern of the discarded. Becareful if you grab it your teleported to a monsters trap.
YEP the monster got smart and set up traps. Sure you get the item but you have to fight your way out.