The popcorn kernels are the Backup General-Later's minions. They where created when he poured Life Powder on regular popcorn kernels, and realized that he had power over them, as a General outranks a Kernel. They became his army of popcorn kernels, and he started crafting little uniforms for every single one of them. Later, they helped him and the Neigh Sayer by sneaking into Colt McClure's hidden base to replace all the spurs on all the cowboy boots by special Project Popovich spurs while her henchmen were sleeping.
One night, CJ falls asleep watching Alita: Battle Angel with his popcorn kernels. One of them, Kernel Redenbacher, recognizing that CJ is asleep and very drunk, decides to go out into the world and explore. When he comes back from his adventure, CJ wakes up and eats them all.
CJ is later attacked by the Reflector, who sneaks into his compound, where CJ is asleep in the couch, in front of the TV playing. The popcorn kernels are in a bowl next to him, and the Reflector uses his powers on them, causing an explosion. All of a sudden, whereas before there were about sixty tiny popcorn kernels in army uniforms, there are now sixty full-grown Channing Tatums in uniform, standing bewildered in the Back-Up General-Later’s living room. He wakes up, and the kernels salute him, before looking at each other and realizing that they don’t have to salute this guy anymore, as he always treated them terribly. A line of sixty Channing Tatums marches out the door, the Reflector hidden among them, stealing CJ's power of popcorn kernels.