Athletically and intellectually gifted, young Benn Grimm, regarded as a future football star as early as forth grade, was nicknamed "Grimm Reaper" for his line backing skills. At the age of seven, Grimm had befriended fellow student Reed Richards, protecting Reed from bullying students. In turn, Reed helped Ben with his studies, tutoring him in math and science; he also shared his research with Ben, showing him his devices built for accessing other dimensions. In fifth grade, Reed was moved uptown to a government research facility. Ben seldom saw his friend thereafter.

Ben finished high school and soon began college in the New York area. He remained in occasional contact with Reed over the years, and when the time came for Reed to demonstrate his teleportation device, Ben was invited to observe. As the test was during Ben's spring break, he rode cross country to the Nevada test site, where he watched the test beside Reed, Susan and Johnny Storm, and Victor Van Damme. The device malfunctioned and Ben woke up in Mexico City, Transformed into a rocky, brutish Thing. He was taken to the Baxter Building by the U.S. government. When the Baxter Building was attacked by Arthur Molekevic's monster, Ben leapt from the skyscraper and battled the beast. Ben, Reed and Johnny pursued the monster into Molekevic's hidden headquarters beneath Manhattan, where they retrieved Susan Storm, though Ben's massive strength inadvertently collapsed Molekevic's chambers. Molekevic hasn't been seen or heard from since, though he may have escaped.

As the U.S. government wanted to keep the foursome a secret, Ben was confined to the Baxter Building for months after his change and limited to weekly phone calls to his family. He accompanied his teammates to Denmark to confront Victor Van Damme, and again into the N-Zone on a voyage of exploration. While Reed and Sue had each other, and Johnny was allowed out in public, Ben was the most isolated of the four, unable to pursue his interests or see his friends, his pro football dreams dead. His first real joy since being changed came when the quartet entered the N-Zone and Ben space-walked for the first time; he found similar moments venturing into the Jurassic Era. After the team went public as the Fantastic Four while battling the alien Nihil in Las Vegas, Ben slowly began to accept what he'd become, even adopting an old football coach's slogan as his battle cry: "It's Clobberin' Time!"