like another user said, the creator of Azumanga Daioh designed the main cast of characters in this anime. but this isnt just passive character design-- the fact that all three of the main characters in Magical Play wear costumes that actually turn out to be LIVING SENTIENT BEINGS is not only part of the character design, but a massive part of the absurdist bizarre and morbid humor, as well as many recurring jokes and memes.
without his specific vision for the characters, even if he did not write direct or produce, Magical Play would not be the same kind of surrealist satire weirdness that it
actually is, because his character designs actively create huge segments of the show's content.
the show also would neatly have fit into a 4koma style of manga if it had ever been one, it has the same episodic-yet-still-overarching-plot-events feel of Azumanga, and despite many "lol so random XD" events at the start, if you watch the whole thing you will realize that it actually does have a plot, and that it's a hilarious satire anime with a dark side to its seemingly dumb and sometimes cliche, but at other times very unexpected and very out there, style of humor.
TLDR: if you've ever laughed at Chiyo-Chan's dad (or been severely creeped out by it) then you will probably find both shows have something unnerving in common.
also, the Shark Girl in Magical Play is basically a prototype fantasy version of Sakaki from Azumanga. 
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