Circus horribilus themed encounter

[Elvenoutrider]

Dear playgrounders - Ive run into a bit of writers block in designing a dungeon. In my campaign, the pcs will face off against a cult disguised as a circus/ acting troup. The cult's plan is to act out a ritual to summon a Lunar dragon (dragonmech), and disguise the ritual as a performance in front of the upper class and nobility. The pcs will be tipped to their plans with just enough time to stop them.The cultists will use a lyre of building to stop the pcs from simply breaking through the doors or walls. This will force the pcs to crawl through the sewers, enter the theater from the basement, and fight their way to the stage.

What I have planned for them to encounter on the way are the cultists themselves, homebrewed "masked monster" (swarms of insects disguised as humans), a gestalt invisible blade/master thrower, identical twin master of masks, a dirgesinger, a doppleganger in a room full of manequins, and an ork "strongman"

Im looking for more circus themed encounters. Right off the bat I think contortionist but I dont know how to turn that into a boss. Party level is going to be around 8 and will be well optimized so no need to be gentle with them.

[Pokonic]

The animals? Inslaved were's trapped in there animal forms. Free them as the fight in there penhouse with the "animal trainer", and you will gain the assistance of were elephants, zebras, lions, the whole nine yards. They might prove to be such a hassle to the preformers that you can sneak into the summoning room as your newfound alies sacrafice themselfs to to kill as many of there tormenters as they can manage.