>>58827606No, the only official depiction is a gen 1 backsprite, and we know how scuffed those are.
In terms of conveying visual information.
We learned from Pikachu and Raichu's designer, Atsuko Nishida, that Gorochu was a planned Raichu evolution who "had fangs and horns and looked like a god of thunder" but was ultimately scrapped because of cartridge storage limitations and GameFreak's realization that they made too many 3-stage mons.
Unfortunately they showed zero interest in revisiting Gorochu for gen 2, because the monumental success of Pokemon as a brand, especially merchandise sales with Japanese girls, spearheaded a massive priority push towards GS having moe mascot creatures they can turn into plushies, and thus Pichu was conceived, totally cucking Gorochu out of a redemption run.
The fact Nishida was allowed to speak openly on Gorochu made it abundantly clear they have no intentions of ever bringing it to life, even in the wake of all the pattern busting GameFreak's been doing that the idea of a 4-stage line, or a Pokemon that can evolve further through normal means after using an Evolution Stone, are mere suggestions for structure rather than hard guidelines to adhere to, like how they made legendaries who can evolve.