R2-D2 has always had a clean character and is not tainted with villainous traits. The faithful robot is synonymous with all the main protagonists such as Anakin Skywalker, Luke, Princess Leia and other good souls.
However, some Star Wars fans always looked at him with a twisted eye, and that makes us imagine him in a villainous role. Jonfer3D at Eat 3D forum has uploaded several [pictures of his 3D project, which aims to project R2-D2 in an evil light. The badass version of the robotic guy comes with several crazy weapons, mean design and a facial expression that tells you clearly that this machine is up to no good.
The designer has created the 3D model with some really amazing textures and colours, which make R2-D2 look evil and scary. Evil R2-D2 has a lot of red and dirty white on his body, and that sort of adds to the evil persona which the animator tries to portray. The Evil R2-D2 model may actually spawn a series of animators trying to vilify most of the good guys so that one can imagine heroes in a different and evil light. It is a fun project, and the comments left by the animator clearly show that he had a great time during this project.
It is interesting how 3D animation can totally change a character and its personality. What is good can be made to appear evil with a few animation tricks, and what is bad can be made to appear holy and angelic, with a few modelling tricks. At the end of the day, it all boils down to expert handling of textures and colors, in order to create an alternative character from the original. You could also take a look at the Star Wars Characters Conceptual Bottles, which serve the purpose of keeping you hydrated and close to your favourite heroes and villains. The Pikachu R2-D2 Mashup Tattoo is a kick-ass idea.