The outfit, as opposed to the makeup, seem to draw more from the comic version of the character as in the comics, Harley Quinn almost always sports a red and black outfit that is reminiscent of jesters in a traditional kingdom court.
At the time, as a recently debuted group, Seventeen were still known for their fun, fresh, and youthful concept.
Does it make you interested in more idols doing gender-bent costumes? The two played up the skinship by Mingyu wrapping Jeong-han in his cape, also fixing his hair while he is at it, sending fans into a craze.
All idols are smart and good and talented and pure as if just born.