The self-described “Underground Rock-n-Roll Circus Sideshow” known as Hellzapoppin’ features stunts like glass-walking, contortion, balloon-swallowing, the homemade lobotomy, walking on razor-sharp machetes, human dart board, and Tibetan Power Yodeling & Throat Singing (OK, we made that last one up) all set to the sound of rock music. 9:30 p.m. (doors 6 p.m.) July 24 at Mavericks at The Landing, Downtown, $13 advance; $20 VIP, The troupe performs again at 10:30 p.m. (doors 4 p.m.) July 26 at Harmonious Monks, Jax Beach, $13,; both performances are intended for audiences age 18 and up.