Before the internet became widespread, cartridge games were a childhood favorite. At the start of a game, weak little monsters would always challenge the hero just to make themselves noticed. That's right, the name of that monster was Slime.
In this modern society, where all sorts of superpower bugs are collectively called “Quirks,” Rimuru Tempest has one too.
His Quirk is a squishy, utterly useless, low-level monster: a Slime that gets KO'd in one hit by a hero.
The difference is that this Slime mutated long ago. So, in a world where crime rates are soaring, the criminals who try to bully Rimuru Tempest, whose original form is a weak little Slime, are in for a miserable time.
The fearsome criminals turn into pitiful little wretches in an instant. “Good grief, who said Slimes were weak and easy to bully, and could be KO'd in one hit? Come out here! I'll beat you to a pulp. (`⌒?メ)”
The fearless terrorists burst into tears. “Waaah (╥_╥)~ Earth is too dangerous! Let's move to Mars to commit crimes instead.”
Meanwhile, his warm and friendly classmates swallow nervously. “Rimuru, is your Quirk really a weak little Slime?”
Rimuru transforms in a flash, shrinking into a squishy blob of pale blue, semi-solid goo like modeling clay. He gloats mischievously: “Wakaka, of course! I'm really just a weak little Slime. (??▽`?)”
Well written, keep it up [already planted]