Medium Loot Bag

Keep these in a box at home and count them. The middle bag of the Halloween event costs ten small loot bags to make, and ten of them in turn upgrade into a large loot bag, the one the game calls a massive haul. About this one the text only says medium level loot. Honest, if vague.

The mistake is carrying them around. Say you upgraded six on a Halloween night and went out to farm with all of them in your inventory. One shot from the treeline and somebody else walks off with your whole candy hunt. Stash them before you leave the base.

Opened, a medium bag is the kind of event loot the costume pages point to. The scarecrow suit and the Mummy Suit have no recipe at all, so bags like this are their likely source. Whether one drops for you is luck, and the bigger bag above it is where the game puts its best loot.