All Gen 1 Pokémon who have Lightningrod can trace it back to the Anime - Marowak due to a line in "What kind of Pokémon are you?", Pikachu did this when fighting Surge's Raichu, Seaking as mentioned before and Rhydon is obvious.But by that point the species was already given Lightningrod, it's not the reason why they have it. Unless you're pointing out it has a horn thing which everyone mentioned and that you can thank Blaine's Rhydon for... despite that's being how it was defeated but I guess someone liked the idea of a Pokemon's horn attracting electricity.