While it certainly can be argued whether or not they are the most popular within their communities, it can't be argued that Deadpool and Pikachu are at least in the top 5 most popular discussion, and now they've been combined.
Granted, it's for different reasons of course. Fans love Deadpool for his sarcastic and oftentimes raunchy wit, as well as his knack for not dying even in the midst of awful circumstances, while fans love Pikachu for his spastic energy and adorable demeanor. Plus, he's really cute, so there's that.
The mashup comes courtesy of the artistic and 3D rendering skills of Ramtraz, who used a mix of ZBrush, 3DS Max, and Photoshop to create the little guy. His work is fantastic, and was even recognized by Deadpool actor Ryan Reynolds, who shared it on Twitter with the caption "I don't know who made this, but thank you. #MaximumEffort."
It's the little things that make such a big difference, like the fact that Pikachu is crossing his arms, but they don't actually cross because his arms are so tiny. It's also humorous how he carries around a spare Pokeball, alluding to possible bounties he has to carry out on others of his kind. That's pretty cold, but a bigger question has to be how he gets that costume around his tail. It just seems like it would be awfully painful.