12-10-12: Edited to include Kholer and Troll.
Here’s a collection of Ascalonian Catacombs videos made since December 8, 2012, showcasing solo Mesmer kills of Queen Spider, Cave Troll, and Lieutenant Kholer (Including his adds, in his room, the way that nature intended). The details of the builds are on the Youtube pages. Thanks to Wethospu for suggesting alternate 2x speed conversion videos. I’m getting an error when I try to embed multiple videos, so only the links for Cave Troll and Queen Spider are shown.
The Kholer fight was definitely the trickiest, for obvious reasons. I ran an illusion-based build, with Feedback for the Ranger, and also the Fern Mastiff for extra distraction. The point of this build was to keep clones and Phantasmal Berserker active at all times, so they could provide distraction and keep cripples on the Mesmer and Kholer, while giving myself a speed buff. Eliminating the Ranger was the most difficult part.
The Cave Troll took nearly as long, due to its regeneration. The trick was to avoid melee range and the AoE while eliminating its regeneration, which can go as high as 25 stacks. I used Mind Stab to remove the regeneration.
Queen Spider was the sloppiest fight, and I would have changed many things with my build if I were to do it again. A Phantasm/no shatter build seems very promising.
I’d like to thank the designers and developers, like you Robert, who spend so much time creating and implementing these fights. Soloing these bosses is in no way practical at all, yet provides a really fun, fresh challenge. It has given me an additional goal and focus while playing.
Lieutenant Kholer with adds:
2x speed: http://youtu.be/dQ-HUnXuw8w
2x speed: http://youtu.be/Up-e-ONUjTo
2x speed: http://youtu.be/YwiCgnLhTk0