Only three things matter in Nintendo's Splatoon universe: Taking down Inklings who like different colors than you, pledging allegiance to Mr Grizz, and music. The performances of pop idols Callie, Marie, Pearl, and Marina are as much a part of Inkling culture as Splatfests, turf wars, and being racist against Octolings.
(To the Inklings' credit, they're working hard on overcoming that last one.)
Given how culturally significant music is in Splatoon, it's not surprising to learn it sometimes goes to weird places. For example, Pearl has a death metal demo that's basically her screaming profanity for 30 seconds before she trashes her instruments.
I mean, I trust what she's saying is profane. The "song" bleeps out the segments where I presume Pearl is telling us all what she has planned for our mothers, but like all Inklings, Pearl speaks a language that sounds like a Furby screaming for its life while being held under water. We're not meant to understand Inklings without the aid of subtitles, therefore we're allowed to disassociate from their music when things get...uncomfortable.
Unfortunately, life is a never-ending pit of pain where humans inflict atrocities upon each other because we can. Enter an Inkling song you can't disassociate from: An Inkling cover of Smash Mouth's 1999 hit, All Star. This project was inflicted upon us by Tristen, aka "Gojira-Sempai," so let's thank them for their work with a rousing course of screams.
That...that's just great. Wonderful. If you want to know how to make your own Inkling pop hit and further speed us towards humanity's deserved extinction, Gojira-Sempai posted instructions on this forbidden magic.
Just make sure to check out our Splatoon 2 tips and guides before you perish.
By the way, this is somewhat unrelated, but Gojira-Sempai is also the author of a Pokémon meme I think about often: