What started as a family hike in North Dakota by two young brothers Jessin and Liam Fisher quickly turned into a once-in-a-lifetime discovery that career paleontologists would kill for.

Along with their dad, Sam Fisher, and their cousin, they identified the remains of a juvenile T. rex skeleton of about 30% completeness, including almost the entire right leg structure, a few vertebrae, the lower jaw, and the all-important hips and pelvis.

It was back in July of 2022 that the teen trio discovered their Cretaceous counterpart in the Badlands. Dad Fisher actually knew the phone number of the Denver Museum of Nature and Science paleontology curator—Dr. Tyler Lyson, whom he went to high school with.

“I didn’t know it was a T. rex, because all I had were photos, and the knee joint looked like a duckbill,” Dr. Lyson told CNN. “Later, I started looking at the photos a little more closely. And the way in which the bone was breaking up into sheets indicated it might be a meat-eating dinosaur.”

He proposed the idea to some of his paleontology friends, who concurred that it was probably a duckbill, at which point Lyson relegated the idea of a carnivore to “wishful thinking.”  It wasn’t until the following summer that the boys were able to take part in retrieving their discovery from the Earth as permission for excavation had to be obtained from the land managers.

The dinosaur-discovering family returns to the site in July 2023 for the excavation.  It was on the first day of excavations, with the kids front and center, that Lyson and his team found the lower jaw full of teeth—shattering the duckbill hypothesis and sending the whole team onto cloud nine.  “The kids were with us every step of the way, which was great,” Lyson added “We realized it was a T. rex on the first day. We had cameras rolling while it was happening.”

The paleontologists who took part in the excavation believe the ‘Teen Rex’ weighed 3,500 pounds, stood 10 feet tall, and was 25 feet long at the time of its death, according to a  Denver Museum.  A fully-grown adult T. rex could weigh over 9,000 pounds and stretch over 40 feet from nose to tail.

“I’m excited for Museum guests to dig into the ‘Teen Rex Discovery’ experience, which I think will inspire the imagination and wonder, not only in our community, but around the world!” said Dr. Lyson in a statement from the museum announcing a new film and exhibit based around the teens’ discovery. 

Captured on film in the new 40-minute documentary T. REX, they will be featured alongside their dino on the museum’s Infinity Theater on June 21.  This giant-screen movie offers an unprecedented journey into the world of T. rex and its fellow Cretaceous carnivores.