Feral children, mutant sideshow, wax museum (with wax made from the fat of humans), and terrified animals. All covered with a thin veneer of civility and wholesome camaraderie.
To elaborate, the posse should be welcomed into the circus proper. Allow the performers to practically faun over their new audience. Make sure, that there are other customers (rubes) as well. A feeling of surrealism and paranoia should rule the day.
Allow them to catch glimpse of things. Two brutish short clawed monsters between tents, surround something smallish and struggling. When the posse walks over it is two beatific children and a small dog. The pooch has terror in it's eyes although he wags his tail dutifully. Allow a tour of the wax museum workroom. Someone will invariably take a sample.
When they are good and paranoid at the magic show; then let them have it. Watch me pull a bloodwolf out of my hat.
Your Fiend and
Personal Hero
Peter F. Kish