The Nightmare Tree in Twilight Arbor - I hopped into an almost completed run of it and the group was having a lot of trouble killing this thing. It took us about 5-10 tries, but we finally got it. :D It felt great to finally beat it!
The Icicle Thing in the Dredge Fractal - The first time we tried killing it, we didn’t succeed. But after doing it several more times, we became total pros at it. :)
Shadow Behemoth - Because the stuff Queensdale map chat says about him is freaking hilarious. xD They treat SB like some kinda perpetually late diva. It’s amazing.