I'm fascinated by imperfections, so I decided to draw the Red/Blue sprite of Kakuna, which appears to have claws. This is often regarded as a sprite error, but could be explained by it being in the process of evolution since Beedrill have similar ones. However, since I drew this one, I've found out it's not an error at all. It's just the... how do I explain this? ...well, check out this link to an official artwork from ages ago.[link]
Please ask for permission and credit if used.