What? Your imagination doesn't work to the point of apparently being willful hallucinogenic delusion? Well, you just need to exercise it more! Get your brain to lift some free weights or something.
In any case, did you really think we were going to make it through this storyline without mixing in some manner of Yu-Gi-Oh!
parody? Even if you have no idea what that is, you should have seen it coming, darn it!
And before anyone asks, no, I have no idea how Justin's "cape" is staying on, and I say "cape" in finger-quotes mode because it's actually just his shirt being worn like a cape. At least in the realm of Grace's imagination, they have the excuse of it being, well, imagination.
As for how it looks like it's constantly in the wind, that's easy: Starch! Lots and lots of starch. You could probably snap it like a cracker.