Rango is one of my favorite movies, and a large part of why is the character design and the art direction. I think Rattlesnake Jake is one of the best examples of that and one of the best animated villains ever from a visual design perspective.
There's the obvious features, he's big, he's a snake, he's got a gun instead of a rattle (which is sick as fuck), but there are choices beyond his visual design that encourage the viewer to look at him and think "yeah, that's a villain".
One big thing is how he moves, he's always taking up a ton of screen space while moving, and with the exception of the couple scenes where he's losing or leaving, we don't see his entire body. He fills the space around him both literally and metaphorically and it really helps to sell the intimidation factor.
Another thing is that he's by far the least humanoid of the speaking characters, the only other character that's as animalistic as Jake is the hawk, who is also universally feared (also Jake is only shown to be scared of the hawk, who is more animalistic than he is, which I find interesting.) Being so significantly more inhuman than the rest of the cast makes him so much more other, and I think it also helps visually sell him as villainous.
There are other things that I think make Rattlesnake Jake a great villain, but I think that visually these things are what's most central to selling him as the big bad (at least in the physical/martial department) and I think they make him a memorable villain.
Overall, Rattlesnake Jake is a great character, with great visual design, who helps make a great movie. I love Rango.
