The climactic scene of Transformers: The Movie features Hot Rod unlocking the power of the Matrix to become a larger, more mature-looking robot: Rodimus Prime, the new leader of the Autobots. The original toy of Rodimus Prime came out in 1986, at about the same time as (perhaps slightly later than) Hot Rod, and is arguably the first Transformers toy ever made that is the same character as a another toy. I say "arguably," not simply because Galvatron (an upgraded form of Megatron) is more or less in the same category, but the fact is that pretty much no one other than me "argues" for anything different. To most fans, it's obvious that Rodimus Prime is, and always has been, a mature version of Hot Rod. There's absolutely no denying the similarity between the toys, nor even the intention that the toys be related. Such similarity simply doesn't happen by chance.
The wiggle room that I'm quick to point out is that neither Rodimus Prime nor Galvatron are explicitly named as being new forms for the differently-named characters they represent on the packages themselves (as the later Goldbug toy would be, as an updated form for Bumblebee). This presumably was done to protect the secret of how the movie would end, but it has the effect of making it appear—at least in the "micro-continuity" of the Tech Specs—that Rodimus Prime is a distinct entity from Hot Rod (and Galvatron from Megatron). Sure, even the Tech Specs for Rodimus Prime drop some hints. "Maturity" is mentioned a few times, as is a tendency to be "hot-headed at times," but that's my story, and I'm sticking to it.
As with Hot Rod, I did not get the original Rodimus Prime toy, but rather a reissue. My Rodimus Prime toy is actually the 2004 Hasbro version, purchased at a point when Generation One toys were finally being clearanced, and frankly still not selling very well. I often say that, by that time, the toys "had the stench of shelfwarmer" about them, and I do think that's at least partly true. If a toy is visibly not being sought after, people start to feel that there's a reason, whether or not there really is one. But the fact is, even by 1986 standards, Rodimus Prime is a pretty pathetic toy. He has even less useful articulation than Hot Rod (which is saying something). As a display piece, I just keep it in vehicle mode (often referred to as the "Winnebago of Doom") most of the time.
As the new Autobot leader, Rodimus Prime does attempt to retain at least one feature that the previous leader, Optimus Prime, had (besides the similar name): a trailer that can transform into a kind of base. There's not much to do with the base, however. In fact, you can barely fit Rodimus Prime's robot form on top of it, and the only adjustable part is the weapon itself (and most of that is needed for transformation). I won't say that I paid too much for this toy at clearance, but it most definitely wasn't ever worth what Toys R Us was charging for it originally. Perhaps some of the reason for the higher cost was the die cast metal. I'm honestly not sure. If so, just add that to the list of reasons I'm glad not to see die cast metal in modern Transformers very often.