I was just wondering, can you make sense of Graveler’s evolution? It’s a rock monster with six limbs and no visible biological features that suddenly becomes a four-limbed reptilian creature with a rock shell. Sure, there have been other strange evolutions, but at least Remoraid’s evolution is going from one living creature to another, how does one go from being mineral to animal? It just looks like Golem was intended for an entirely separate evolution line.

Hmm.  Faced with a weird evolutionary line in the first generation, my instinct is go to the hex numbers and see what patterns turn up (if anyone’s unfamiliar with what these are, they’re the numbers that represent the order in which Pokémon were originally programmed into Red and Blue, and probably the order in which they were created).  Of the three, Graveler comes first, followed by Golem ten places later.  Both are within the first 1/3 of the sequence, where there are relatively few intact evolutionary families – the only related Pokémon who appear close together this early are male Nidoran and Nidoking, female Nidoran and Nidoqueen, and Hitmonchan and Hitmonlee (who at this stage were ‘related’ but not by evolution).  Some of those designs may even predate the concept of Pokémon evolution, although that’s a very speculative suggestion.  Shortly after Golem, complete families start to occur more often.  Geodude turns up far later, among the final 30 designs, 10 of which didn’t even make it into Red and Blue.  It’s entirely possible, even likely, that Graveler and Golem were not originally conceived as related creatures, and were combined into a single lineage after the fact – something which may actually have happened at a relatively late stage of the games’ development, concurrently with Geodude’s introduction.