Common Problems
I have the Sinister Squashling and Hallowed Helm for Hallow's End achievement Sinister Calling but didn't receive credit for the achievement.To earn the Sinister Calling achievement you must obtain the Sinister Squashling pet and and the Hallowed Helm on a single character. You can complete this achievement over multiple years. For example, you can obtain the pet one year and the helm the next year and it will still count for the achievement.
The Sinister Squashling will only count if you obtain it from the Loot-Filled Pumpkin or if you purchase it with Tricky Treats. Having someone trade you the pet or buying it on the auction house does not count. In addition, the pet must be learned and added to your collection.
In Wrath of the Lich King Classic, if you obtained the items during the Burning Crusade Classic expansion, they won't retroactively grant the achievemnt. In addition, the Sinister Calling achievement was removed from the Hallowed by the Name meta-achievement on October 26, 2023.