Wild Asian equines / SUN 8-30-20 / Soleus muscle locale / Pitch Perfect a cappella group / Pop singer known for wearing face-covering wigs / Magical resource in Magic the Gathering

Constructor: Olivia Mitra Framke

Relative difficulty: Easy-Medium (9:45)

THEME:"All Aflutter"— a puzzle about the BUTTERFLY EFFECT (81A: Subject of this puzzle, as suggested visually by its central black squares), which is apparently a concept in CHAOS THEORY (24A: Mathematical field that includes the 81-Across); the grid includes a "definition" of the concept (ONE SMALL THING / CAN MAKE ALL THE / DIFFERENCE / IN THE WORLD) (3D: Start of a definition of the 81-Across) and then for some reason you have to add the letter "N" (?) to a "shaded square" (not depicted, but visible in the paper and on the app), which turns TOR and ADO into TORNADO (62A: A.L. East team ... or, using the shaded square, what a little movement by this puzzle's subject might cause), which I guess illustrates the idea of a "small change" making... "all the difference in the world???" I don't know. Black squares near the middle of the grid also kinda depict a butterfly 

Word of the Day: MANA (????) (35A: Magical resource in Magic: The Gathering) —

Magic or mana is an attribute assigned to characters within a role-playing or video game that indicates their power to use special magical abilities or "spells". Magic is usually measured in magic points or mana points, shortened as MP. Different abilities will use up different amounts of MP.^[1] When the MP of a character reaches zero, the character will not be able to use special abilities until some of their MP is recovered.

Much like health, magic might be displayed as a numeric value, such as "50/100". Here, the first number indicates the current amount of MP a character has whereas the second number indicates the character's maximum MP. In video games, magic can also be displayed visually, such as with a gauge that empties itself as a character uses their abilities. [...] 

"Mana" is a word that comes from Polynesian languages meaning something along the lines of "supernatural power". The concept of mana was introduced in Europe by missionary Robert Henry Codrington in 1891 and was popularized by Mircea Eliade in the 1950s. It was first introduced as a magical fuel used to cast spells in the 1969 short story, "Not Long Before the End", by Larry Niven, which is part of and later popularized by his The Magic Goes Away setting. It has since become a common staple in both role-playing and video games.

That "definition" is such an awful cliché. And it's not even a "definition," it's a dumb saying. If you were truly dealing CHAOS THEORY, my guess is you'd provide a proper definition, but instead we get this mushy pop mumbo jumbo, "ONE SMALL THING / CAN MAKE ALL THE / DIFFERENCE / IN THE WORLD"; like, if someone said that to me, I'd slowly or possibly quickly just find somewhere else to be. Also the whole butterfly flapping its wings and causing a TOR(N)ADO ... somewhere, anywhere, is another bit of nonsense. Again, I believe that there is a thing in CHAOS THEORY called the BUTTERFLY EFFECT, but the pop understanding of it flaunted here is just garbage. Weirdly, I think I first understood the BUTTERFLY effect as an effect through *time*, not *weather*, i.e. I thought it was the idea that if you went back in time and killed a single butterfly (why you would do that, I don't know, you cruel bastard) then the "effects" across large amounts of time could be world-alteringly significant. But sure, no, butterfly flaps cause tor(n)ados, that works too. Seriously, the wording on the "definition" is the Main Thing making me not like this puzzle at all. I kept thinking it was going to be something specific or at least snappy, but ... no. Also, why ... what is the rationale for entering the letter "N," specifically, in that "shaded square" (between TOR and ADO)? "Using the shaded square"?? Does "using" mean "putting an 'N' in there for some reason." I hate stuff like this because I feel like "ugh do I have to read every clue again to see if *somewhere* the 'N' rationale is explained!?" But I don't think it is. Just ... arbitrary. Put an 'N' in there. TOR(N)ADO. Whoopee.