The RNG gods might have smiled upon me this year, but they certainly didn't for my wife who tried in vain to loot the Sinister Squashling on her main toon throughout the two week Hallow's End world event. Which of course means she now has to wait an entire additional year, and hope she loots the squashling next year (she didn't get it last Octobr either) in order to complete her "What a long strange trip its been" meta achievement for her purple Proto-Drake mount. We were curious, and she put in a ticket, to find out just how many attempts she made to trick-or-treat, and how many times she actually killed the Horseman. It'll be interesting to see if, or when, Blizzard responds to that because it is simply ridiculous to put that kind of RNG into a process that takes a full year to complete.
And if she doesn't loot it again next year?