SMG4: If Mario Was In... Splatoon is the twenty-eighth episode of Season 7 and the three hundred and fifty-fifth overall to be uploaded by SMG4.
Mario finds himself in the colorful world of Splatoon! A Splatoon tournament is about to begin and Mario wants to compete... Will he be able to win it!?
The video begins at Peach's Castle, where Mario, Peach, and Toadsworth are painting up the castle; though, while Peach and Toadsworth are actually painting the walls, Mario just draws a derpy face and writes "A$$" on the wall. Toadsworth then asks Mario if he could get some more orange paint, Mario agrees and goes to the basement to look for it.
Eventually, he finds the orange paint can and pelvic-thrust-opens it. Shortly after that, the can suddenly start to shake, leaving Mario surprised, then flips over and spills him over with the paint itself. Mario suddenly spots an orange squid hopping around and tries to catch it, but he fails as the squid drags him into the pipe while the episode's title appears.
The two eventually approach a Japanese-looking city, which appears to be Inkopolis from Splatoon world. While Mario is utterly amazed by the city, the squid that Mario encountered quickly transforms into a girl with orange tentacles instead of hair, which appears to be an inkling, also from the Splatoon universe. Thinking it was Mario to trap her into that can a day before the start of the episode, the inkling girl tries to threaten him. Mario gets very surprised by approaching a talking squid, so he asks the inkling if he is in Bikini Bottom, just to be splatted by her. The inkling then quickly introduces herself as Meggy, the "upcoming star". Suddenly, Meggy finds out that she's late for training and runs away while Mario flips her off without looking.
As Meggy leaves, Mario is left still wondering what is the place he ended up in and thinking how to get out of there. He tries to blend in by inadvertently running around and making Zoidberg's gibberish noises until he bumps into Cap'n Cuttlefish, who tries to greet him. Thinking that Cuttlefish looks wise just because he's old, Mario tries to ask him how to get back home. Instead of telling the way home, Cuttlefish just starts to tell Mario random stories, much to the plumber's anger. Although Mario tries a few more times to seek the answer, the old inkling annoys him so much that he kicks him out.
Eventually, Mario sees Spyke the sea urchin selling stuff in a corner. He then approaches Spyke and asks him if this place is where he can order some spaghetti. Spyke answers him that he doesn't sell any spaghetti and that Mario can purchase "sum deadly power ups" instead, one of which are Super Sea Snails. Mario mistakes those snails as some kind of mushrooms, quickly devouring one of them - just to find out he himself transformed into a snail.
In the next scene, Mario is back to normal, complaining that he's probably going to live like a squid forever. After a brief moment, he notices the Squid Sisters announcing the Turf War Tournament and gets cheered up quite a bit. While Callie and Marie wonder who was the guy staring at them behind the glass could be, Mario manages to approach them and ask them about the tournament he had just heard about. Callie then answers him that anyone can join that tournament as long as he/she has three other people in his/her team. Mario suggests the Squid Sisters join his team but gets understandably rejected and kicked away. He starts to complain about how he's going to find the team until he meets Meggy again and follows her to the training ground.
There, on the training ground, Meggy is showing all her splatting strength, splatting up all the targets until she accidentally splats the suddenly appearing Mario, whose face, as she implied, "looked like a target". Mario then asks her if he can join her team, but Meggy doubts it, laughing and then claiming that her team, called Splat Squad, is already full. Mario notices that the fourth member of the Splat Squad is Heavy Squid, whom Mario mocked for "not even looking like a squid". However, Heavy Squid does not seem to be insulted much. Meggy just reminds Mario that he does not have any skills, although nothing of what just happened seems to stop Mario. He decides to prove that he does have skills.
Mario then starts to shoot a machine gun inadvertently, accidentally shooting up an inkling boy and passing the gun to Cuttlefish, mistaking the other inklings and octolings. While distracted, they all run up to Cuttlefish, blaming him for shooting the innocent inkling, and try to threaten him. Meanwhile, Meggy and Heavy Squid transform into squids and cross the huge spillage of paint. Mario tries to cross it as well but fails since he's a human and cannot turn into a squid. Another member of the Splat Squad, an orange inkling boy transforms into a squid, then he makes a massive jump and, finally, lands just near to Meggy. Mario just uses his cannon to launch himself to them, but misses and crashes into Heavy Squid, thus severely damaging him.
As the inklings complain about Heavy Squid's leaving the Splat Squad, Mario sees his chance and tries to join their team. After a series of failed attempts, he is finally accepted into the Splat Squad. Although he is told not to screw up anything, he does really screw up everything, being really unable to shoot, aim or use the paint roller, or thinking that the Paint Bomb is some new type of Doritos. Later, Mario and Meggy are seen sitting together on the skyscraper's roof. Despite all Mario's fails during the training, Meggy admires him for being "quite alright". Continuing, Meggy asks Mario if they are going to win the Turf War, Mario answers that he frankly has no idea.
The next day, the Turf War begins, and the orange Splat Squad proceeds to face the blue Ink Brigade. The Splat Squad, headed by Meggy, tries to do all its best to flank the Ink Brigade. Mario does so as well but doesn't really seem to succeed at all. Even being told by Meggy to follow her lead doesn't help him much. Meanwhile, Callie announces that the teams only have a minute before the tournament ends. As Meggy tells Mario to "stop messing around", Mario now really tries to do all his best "the Mario way" until the tournament ends.
Callie then announces the results. And the winner is, much to Meggy's dismay, the Ink Brigade. Meggy despairs and complains about the Splat Squad's loss. Although Mario is usually selfish and careless, here he does show all his niceness, much to the viewers' surprise, and supports Meggy. He tells her that no matter how much spaghetti you eat, there will always be meatballs left over, lightening the inkling's mood up. Meggy then claims she just has to train harder next year.
Later, at the Inkopolis' main square, Mario and Meggy share some parting words with each other before Mario leaves the Inkopolis and goes back to the Peach's castle. The video ends with Mario poking out from the pipe that he was dragged in by Meggy yesterday and saying he had a funny time there in Inkopolis, but then gets punched by Toadsworth who complains about Mario "getting paint in the goddamn house."