Fossils found in the last 30 years have altered our traditional vision about Tyrannosaurus Rex. Paleontologists now suggest the dinosaur had at least some feathers and their babies could have had a lot of downy plumage. T. Rex probably speed-walked rather than ran, and their tiny arms probably weren’t useless appendages after all, instead used for grasping prey.

Many of the dinosaur’s traits remain rather fuzzy, like what color T. Rex was and what it sounded like. But a new exhibit at Chicago’s Field Museum adds another sensory detail to the mix: how T. Rex’s breath smelled.

Taking a whiff of meat-eater breath is part of Experience SUE, an addition to a private, 5,100-square-foot "suite" containing the bones of the most complete T. Rex fossil ever uncovered. The new sensory stations are designed to let visitors do more than just stare at the fearsome bones. They can touch recreated patches of the dinosaur’s skin and listen to what researchers currently suspect the dino sounded like. And then there’s the smells—yes, that’s plural.

The museum wanted to bring a vast smellscape of the Cretaceous alive, so it commissioned the development of four scents that would have been around when SUE roamed the prehistoric landscape of Hell Creek, South Dakota, where her fossil was unearthed, reports Jessica Leigh Hester at Atlas Obscura.

To create the scent of the ancient plants, Field Museum paleobotanist Az Klymiuk took a look at the plants that existed at the time, finding modern counterparts. That included broad-leaved trees that were likely similar to cypresses, redwoods, and tulip trees. Prehistoric ponds were covered with plants that resemble today’s water lettuce. The team was able to develop long-lasting modern analogues for three scent stations dedicated to Cretaceous plants, including cypress resin, ginger root and tulip trees.

“End-Cretaceous floras are pretty similar to a hardwood-dominated swampland today,” Klymiuk tells Hester. “I think of Hell Creek being similar to Northern Florida or South Carolina. It’s not an alien landscape at all.”

For the fourth station, they wanted the scent of SUE herself. At first, Hester reports, the team attempted to recreate the scent of T. Rex poo. But they soon gave up when they found most commercially available fecal scents were based on human waste. (If you desperately want to smell T. Rex's waste, hyena poo is probably a pretty close match because like SUE, hyenas eat flesh and bone, says Meredith Whitfield, exhibit developer at the Field Museum.)

Recreating SUE’s breath, however, seemed more doable. “From anatomical studies of SUE’s teeth, we can say, ‘Well, you have the kind of anatomy that might suggest that you have some nasty raw meat decaying in your mouth,’” Whitfield tells Hester. “What did that smell like? The answer is: Bad.”

The museum contracted with a company that concocts smells, finding one scent called “decaying flesh” that fit the bill nicely. However, the scent was so foul they were worried it would make visitors physically ill. So they diluted the scent until it no longer made people gag.

The big question is, did SUE’s breath actually smell like rotting flesh? Whitfield says she doesn’t believe the metabolic functions of bacteria that break down rotting meat have changed much even over millions of years. “I have no doubt that rotting meat today smells like rotting meat in the past,” she tells Hester.

The exhibit appeals to other senses as well. According to a press release, the most recent research suggests T. Rex likely sounded like a crocodile or a heron-like bird called a bittern. For the exhibit, the team took the vocalizations of these modern creatures and scaled them up to match SUE’s body size. Visitors not only hear the low grumblings, but can also feel the vibrations when standing on certain sections of a platform.

Researchers from the Black Hills Institute of Geologic Research, which creates fossil replicas for museums, worked with Field Museum paleontologists to create patches of T. Rex skin that visitors can touch, along with skin from Triceratops and an early mammal called Didelphodon.

Luckily, the museum decided not to let visitors experience what the bite of a T. Rex felt like, which was probably even more deadly than SUE’s breath.