I just mentioned this a couple days ago, that all I needed was the Sinister Squashling, and the Hallowed Helm to complete my Hallow’s End meta achievement, and by extension the “What a long strange trip it’s been” achievement, with the Violet Proto-Drake reward.
Not only did the Hallowed Helm drop yesterday afternoon, but I actually won the roll! Got the Squashling pet the evening before Trick-or-Treating in Dalaran. Gotta say… loving the new mount. Now to continue the year long process on my two other main characters.