Where do you even start with this one? First off, I guess, let's just say that the Horror and Tragedy tags are completely deceitful. The only Horror in this manga is related perhaps to the inspiration for the shark itself, but even there it's more of a B Movie horror thing. Think "Sharknado" more than "The Ring" or even "Jaws" for that matter.
So the premise is: a dumb but innocent (read: too dumb to read the room) girl has discovered she has magic and encouraged by her friends, goes to attend the summoner's school. Twist is, everyone in this world can do as much as she can so she's not really exceptional and her friends are literally just assholes making fun of her, but she doesn't know that because she's dumb.
At the summoner school she does her best but is still among the weaker students. However her teacher still gives her a chance to summon her own partner! Twist is, everyone at the school is an asshole, treats her like dirt and the teacher is actually just a massive bitch.
She summons a baby shark (no singing!) because she is dumb and fails the process (kinda, not really, ofc) and everyone laughs at her and the shark. It is then revealed that the shark has a passive effect that makes it hate "normies" and it identifies all students in the class as such. It then goes berserk and tries to kill/eat/maim all of them. It is level 700+ and the students are Level ~50. Guess who wins?
It's the shark... after it turns in to a fifty foot, three headed, tentacle shark. Yeah... it... gets weirder from there.
So this is gory but the blood may as well be tomato juice for how relevant it is. This is a gag manga where the gag is: "motherfucking shark eats everyone!" and it kinda goes from there. It's all played for laughs and while the art can go places, the general atmosphere really keeps things light... and weird for the most part.
Give it a shot if weird eclectic Japanese gag manga stuff is down your alley. Just be ready for the gallons of blood and the sharknado... There is one in the first 10 chapters of this and it is explained in detail (hah!) why flying sharks being carried by a tornado is completely logical and not at all insane. I'm not joking, there is a corner that explains this.
It is weird. I love it! Not just because it's weird, mind, but rather because it's unrelenting with just how weird it is. Lots of stuff is weird but it usually keeps the baby shark turning into a 50-foot three headed octo-shark for a second or third chapter rather than the very first. As the translators have helpfully pointed out before the first chapter starts, this manga has jumped the octo-shark from panel 1.