Apparently round hot dogs are a thing that exist as discovered by writer Maria Yagoda of Food & Wine. You're probably just thinking it's bologna and you're kind of right, though the creator Rastelli's claims there are key differences.
In a patented process, Rastelli's chops black angus beef and premium pork, rather than fully emulsifying or liquifying the mixture like what's done for many traditional bolognas. "We then wrap our meat mixture in a collagen casing, followed by a netting to help hold shape," a spokesperson told me. "The product is then smoked, similar to an Old World-style hot dog, with a proprietary blend of woods, such as chicory, and later finished in the oven. Before slicing into rounds, we remove the casing." They remove the casing so the meat becomes more permeable, allowing the flavor of the condiments to "really sink into the round dog," and to help reduce the chances of choking.
So, yeah, that's a lot of words to say it's pretty much just thick bologna. Although this further complicates the eternal debate: is a hot dog a sandwich?
You can buy an 8 pack from Rastelli's for $18. Or you can buy a normal hot dog from Costco for $1.50 and get a drink as well.