Here's an easy one we don't seem to have (at least not under any "obvious" title). It's when the art style on an anime, cartoon, comic, or somesuch doesn't match the story or the themes. Needless to say, it can be intentional or unintentional. If the "intentional" variety already falls under Stylistic Suck
or something like that, then this can refer just to the former.
I swear I had like five of these when I came up with it in the shower, but now only one remains in my head. :(
Is it tropeable? If so, any others?