Bumbles

Steps to finish the achievement:

1) Go to the Mildenhall Meadery in Stormsong Valley and kill Flowing Honey. They have a very low chance to drop Annealed Honey Amulet.

2) When you get the amulet go to Boralus. In the northern area of the city at 51, 47 is a shop called Scribes & Nobles. Talk to Rosaline Mildenhall inside. After she tells you her story you'll receive Rosaline's Letter. She does have multiple spawn points throughout Boralus, this is just the one I found her in.

3) Take the letter back to Mildenhall Meadery to Ancel in their laboratory basement. Give him the letter and you'll be given a new quest called Bumbles the Bee. It sends you to the other laboratory in the cave at 73, 72 just up the hill. On the table inside is Raimond's Secret Ingredient. Pick it up and take it back to Ancel.

4) Ancel will give another quest afterwards called Let's Bee Friends. It's a daily quest that has you create Mildenhall Growth Formula by picking up Vial of Honey Slime items from the mobs outside. You use them to create the formula which is then fed to Bumbles next to Ancel. You can do this only once a day and after seven days you'll receive the achievement and the pet, Bumbles.

Enjoy!