S̶M̶G̶4̶: I Can't Believe It's Not SMG4! is the twenty-sixth episode of Season 10 and the five hundred and eightieth overall to be uploaded by SMG4.
SMG4 and his friends attend a play Mario plays in, but it seems awfully familiar.
The story begins at Peach's Castle, where Mario arrived, having ruined the gang's playtime with Jenga, with a reasonable explanation that he got cast in an upcoming play, set to be shown in the Gielgud Theatre in Aubergine, Mushroom City, with a little story on his audition.
At the Gielgud Theatre, Cromulus, the god of art, is running his audition, with a lot of actors trying to get a role in the play, including Mario, Belle Fontiere, JubJub Boopkins, Rob the Scarecrow, Whimpu, a Luigi Doll, and Melony, who got the roles. Cromulus then started the rehearsals for the play.
2 hours later, the Gielgud Theatre opened to spectators, watching the play, with the gang attending. As the play starts, in which it all seems too familiar to the gang as the scenes are somewhat similar to scenes from episodes from season eight, season nine and early episodes of season ten. These included:
- SMG4: Mario and the Anime Challenge: Belle, Rob, and JubJub Boopkins appears, with Belle asking Mario to do anime. Belle appearing made Tari suspicious (She's Tari's rival in Meta Runner), before a pillow drops on Belle's head, and Rob, JubJub Boopkins and Mario celebrating.
- SMG4: If Mario Was In... Splatoon 2 Mario talked to Melony about training for the "Water-fest", before another melon representing Desti appears and Mario shooting a burst of water. The three ended up shooting water crazily. This got Meggy suspicious as Waterfest sounded vaguely familiar to her. (Splatfest)
- SMG4: Mario And The T-Pose Virus: Mario shouted to the A-posing zombies about the death of his brother, before Rob asked if they could settle it with a bite of corn. Mario then proceeded to kick Rob to the A-posing zombies. Belle sighed about who wrote the script as the rest of the crew attacked Rob.
- SMG4: Mario Gets His PINGAS Stuck In The Door: Mario gets his butt stuck on the door, with Weegee doll, JubJub Boopkins, and Rob giving their reactions.
- SMG4: Mario and The Diss Track: Rob rapped about corn for the first ten seconds, then Whimpu pushed him over, and with Mario and Melony, started singing "Mine Diamonds" in a similar manner to Saiko's song Darkest Hour. This time, Saiko is the one who's shocked, before looking at an equally confused Bob Bobowski.
- SMG4: Final Hours: Melony kicks watermelon Desti's coffin into a pool of water, very loosely reenacting Desti's funeral in Final Hours.
SMG4 found SMG3, exiting Cromulus, and yells at him. He was overpowered when Anti-Cast surrounded him. Fortunately, he soon was backed up by the rest of the gang, which then quickly escalated into a fight. Then, Mario was able to stop the bickering between the two content creators and led to a truce between two factions (although SMG3 still had a grudge). The two factions finally came to an end, calling for peace with each other, and both went their own ways. Mario, undecided about which gang to follow, decided on an ultimatum that he splits himself, with both his head and body following each gang, ending the episode.
- Meggy Spletzer
- Saiko Bichitaru
- Fishy Boopkins
- Bob Bobowski
- Belle Fontiere
- JubJub Boopkins
- Luigi Doll
- Rob the Scarecrow
- Kermit The Frog
- Bowser Jr.
- King Bob-omb
- Monty Moles
- Bullet Bill
- Mr. Blizzards
- Chain Chomp
- Koopa Troopas
- Buzzy Beetle
- Mecha Koopa
- Cheep Cheeps
- Watermelon Desti
- Lanky Kong
- The French Narrator
- Every SMG4 story arcs is referenced in the play:
- The Waluigi Arc: Mario is seen throwing Rob the Scarecrow (acting as Bob Bobowski) to the "A-Pose Zombies, re-enacting the events of SMG4: Mario And The T-Pose Virus".
- The Rapper Bob Arc: The events of SMG4: Mario and The Diss Track are re-enacted. Likewise, before the play started, Bob states that he misses the glory days of his rapping career.
- The Anime Arc: Scenes of Mario, Rob, JubJub Boopkins and Belle in an anime contest, Melony training and fighting a watermelon version of Desti in "Water-fest", and the watermelon Desti's funeral are shown. These took place during the events of SMG4: Mario and the Anime Challenge, SMG4: Meggy's Bootcamp, SMG4: If Mario Was In... Splatoon 2 and SMG4: Final Hours.
- SMG4: Mario Gets His PINGAS Stuck In The Door: The blooper is parodied, but with Mario's buttocks instead of his Pingas.
- SMG4: Bowser Loses Custody Of His Children: Bowser has regained a bit of his bad habit of child abuse.
- At 14:20, when Mario's head and body split, Mario's eyes are the wrong expression (Shocked instead of happy) for a frame.
- In the title, the word SMG4 is crossed out, similar to S̶M̶6̶4̶: `•.¸¸.•´´¯`••. .• ( Tubbie TV ) •. .••`¯´´•.¸¸.•`.
- With the appearance of Belle Fontiere in the episode, this makes her the first Meta Runner character other than Tari to appear in the SMG4 series, discounting Theo's cameo on the box art for Super Smash each other in the ass Bros. 3D Dream Drop Distance & Knuckles in SMG4: The Big Bad Bully.
- This is the first time JubJub plays an antagonistic role.
- This is the second blooper to not take Desti's death seriously, after SMG4: Mario's Magical TV.
- When the narrator for Mario's play promo reads the disclaimer, a long list of various 1000 Ways To Die episodes is quickly running past the screen.
- On July 13, the scene at 8:52 parodying Final Hours was altered for unknown reasons, the original version played a low pitched version of "Emotional Titanic Flute" by New Zealand comedian Matt Mulholland, but it was changed to a generic sad song. It is believed to be changed to avoid copyright infringement.
- I Can't Believe It's Not Butter!: The title and thumbnail reference this product, but with "SMG4" in place of the word "butter" and SMG4's character on the tub instead.
- The Phantom of the Opera: This blooper is parody to this novel by Gaston Leroux.
- In this blooper, the SMG4 characters play the following characters:
- Erik: SMG3
- Christine Daaé: Belle Fontiere and Tari
- Vicomte Raoul de Chagny: Mario and SMG4
- The Persian: Whimpu
- Comte Philippe de Chagny: Luigi
- Armand Moncharmin and Firmin Richard: Fishy and JubJub Boopkins
- Madame Giry: Saiko Bichitaru
- Meg Giry: Meggy
- Debienne and Poligny: Rob and Bob
- Carlotta: Melony
- In this blooper, the SMG4 characters play the following characters:
- Hamilton: The poster for the play is a reference to this musical.
- Furthermore, this possibly references the release of the musical as a film on Disney+ on July 3, 2020.
- SpongeBob SquarePants: The French Narrator can be heard in the background saying "Two Hours Later".
- Rick and Morty: Cromulus even incorporating the "Show me what you got!" meme.
- Avatar: The Last Airbender: The whole video is most likely referencing "Avatar: The Last Aribender" Book 3's episode, "The Ember Island Players". Both stories have the main characters watch a play about their adventures throughout the series and the play(s) show inaccurate portrayals of the main characters.