Okay, first of all, that's not what we mean by "adult." Get your mind out of the gutter.
No, these are variant covers for DC's January titles that are jumping on the hot new trend of coloring books marketed to adults. It might sound a little childish, but the act of taking crayons to a piece of paper can be really soothing and help manage anxiety. The only real problem with them is that unlike their kid-oriented counterparts, the ones marketed towards grown-ups tend to suffer from a distinct lack of superheroes, instead relying heavily on boring ol' geometric patterns and shapes. Shapes! Who in the world is relaxed by shapes?!