Technical rehearsals for The Wizarding World of Harry Potter at Universal Studios Hollywood are underway — and the initial reviews are literally stomach-churning.Harry Potter and the Forbidden Journey, the wilder of the attraction's two signature rides, employs 3-D technology and wraparound screens to whisk passengers away on an immersive airborne adventure. As described by the Los Angeles Times, riders are seated on benches that move around, as if guests are flying behind Harry himself. Simulated dragons, spiders, and other obstacles swoop in and out along the way.But while the 3-D twists and turns are technically and aesthetically impressive, they don't sit well with all test riders. TMZ reports the Forbidden Journey is inducing nausea and vomiting. Engineers trying to find a fix might need some magic up their sleeves, since motion sickness is a common side effect of 3-D and virtual-reality tech.Fans with weaker stomachs might prefer the family friendly Flight of the Hippogriff, a Potter-themed outdoor roller coaster. Also, this fourth Wizarding World of Harry Potter location, slated to open April 7, will feature new landmarks to explore throughout the Hogsmeade wizarding village, including the Three Broomsticks pub and eight souvenir outposts.In the meantime, muggles can test whether their tummies can handle going on the Forbidden Journey with the video preview, below.