Return of the Mammalians (mission)

"You ooze, you lose. Go back to Ursa WHINER!"

- Frye to Mr. Grizz right before the battle begins.

Return of the Mammalians is the sixth and final phase of Alterna Space Center in : Return of the Mammalians.

Boss Appearance
After having three of his Fuzzballs splatted, Mr. Grizz absorbs all the Fuzzy Ooze on the rocket and grows into a ginormous size, knocking Agent 3 and Smallfry away in the process. They are saved by DJ Octavio in his modified Octobot King L3.Gs. Smallfry then transforms into the Hugefry after hearing Calamari Inkantation 3MIX performed by the Squid Sisters, Deep Cut and DJ Octavio. Hugefry will battle Mr. Grizz while Agent 3 and DJ Octavio vacuum up four Fuzzballs on Mr. Grizz's body.

Walkthrough
''Note: Due to the level having no fee, you may retry as many times as you want. However, this "stage" has no checkpoints.''

Agent 3 will need to pilot the Octobot L3.Gs and use the Ink Vac to suck in four Fuzzballs on Mr. Grizz's body, before firing the ooze back at him under 3 minutes and 33 seconds.
 * Octarian enemies will appear as the Fuzzballs are being sucked in. Agent 3 must defeat these enemies before they continue. Possible combinations include:
 * An Octotrooper and an Octocopter
 * Two Octohoppers
 * Two Octostamps, and one Amped Octostamp
 * Three Twintacle Octotroopers
 * Two Octobombers, two Deluxe Octocopters, and a Shielded Twintacle Octotrooper

It's possible to get hit by the fake Fuzzballs or Mr. Grizz or Hugefry while fighting Octarian enemies, as the player cannot pilot the Octobot while fighting. Repeatedly getting hit will not cause Agent 3 to get splatted or impact their health, but will severely hinder the progress of sucking in the real Fuzzballs.
 * After the player destroys one Fuzzball, fake Fuzzballs will appear on the way to the real Fuzzball. These resemble gigantic Burst Bombs coated in Fuzzy Ooze, and will float around in set paths to block the player from reaching Mr. Grizz. Making contact with them or trying to suck them in will break the player's armor and cause the Octobot to be knocked back a small distance.
 * Being hit by Mr. Grizz or Hugefry will also cause the Octobot to be knocked back.

Once all Fuzzballs are sucked up, DJ Octavio will reverse the effect of the Ink Vac, allowing Agent 3 to send back the Fuzzballs at Mr. Grizz, defeating him.

If the player fails during this phase by either getting splatted by the enemies or running out of time, a cutscene of the Earth being covered in Fuzzy Ooze, and the Inklings and Octolings turning into fuzzy creatures as O.R.C.A. reports that the Earth has turned into a giant Fuzzball, will be shown before the usual "Continue?" screen shows up. Mr. Grizz can also be heard laughing while the cutscene plays as the screen turns white. A hollow siren-reminiscent cover of some song plays over this.

Enemies and Mechanics

 * Octotrooper
 * Shielded Octotrooper
 * Octocopter
 * Twintacle Octotrooper
 * Shielded Twintacle Octotrooper
 * Octohopper
 * Octostamp
 * Amped Octostamp
 * Octobomber
 * Fake Fuzzballs

Quotes
For a list of quotes during the mission, see Return of the Mammalians (mission)/Quotes.

Trivia

 * Similar to the final boss mission in Octo Expansion, the final phase involves the player defeating the boss under a time limit, and failing this phase will cause a cutscene of the aftermath to play while a siren-reminiscent cover of a track plays (Color Pulse in the Octo Expansion's case). Also, when DJ Octavio fires the ooze back at Mr. Grizz, the UI will begin to glitch out, and in Octo Expansion, when Pearl fires her Princess Cannon at the NILS Statue, the UI also displays unusual things as the result bar breaks and the percentage goes up to 888.8%.
 * The 3 minutes and 33 seconds time limit, as well as Calamari Inkantation 3MIX, are references to the number 3, as it is a common theme throughout Splatoon 3.
 * During the final phase, as the time passes, the surroundings will get progressively redder and hotter. This is a reference to how near-Earth objects gain heat as they make contact with the Earth's atmosphere, as Mr. Grizz is heading to Earth himself like one.
 * In the Japanese, Korean and Chinese versions, instead of showing the title in the language directly, the English title 'Return of the Mammalians' is shown, with the respective translation below it and with a smaller font.
 * Before the final phase begins, DJ Octavio refers to Calamari Inkantation as "the heavenly melody" himself, suggesting that he is likely also affected by the song, or if not, at least is more willing to accept it than before.
 * After the first time the player gets the bad ending during an attempt, O.R.C.A will not comment on it.