SMG4: Stupid Mario World is a blooper uploaded on December 16, 2017.
Mario and Yoshi travel across MAGICAL lands to meet up with his boi Bowser. But Bowser Jr and the koopalings really don't want him there.
The blooper starts off with Mario riding on Yoshi texting, Mario is excited to go over to Bowser's Castle since he was invited to by Bowser after seeing his bouncy house. Yoshi asks why Mario never visits him, which Mario replies that he visits Yoshi when he's too lazy to walk which Yoshi is not amused by.
Meanwhile at Bowser's Castle, Bowser was jumping in the bounce house when Bowser Jr. comes outside and starts yelling, stating that he heard that Mario was coming over to play in his bounce house. Bowser tells Junior that he was the one who bought it and that they only hate each other when Peach is involved. Junior tells him that Mario is mean to him which Bowser asks him to name one time.
He recalls back to the times were Mario flew him around, ran him over with his kart, mocked Bowser Jr. in his clown car, rammed him again while sitting on a roof. But Bowser doesn't really care saying it's not his problem and continues bouncing. So Bowser Jr. Gathers the Koopalings to get Mario.
Starting off in World 1: Yoshi Plains, Mario and Yoshi are going on their way. During this Mario complains to Yoshi that he's too slow and to go faster, Yoshi insults Mario by calling him a fat-ass which he hears and Yoshi takes it back. Afterwards they encounter Iggy Koopa in his Clown Car. Yoshi advised to watch out but Mario thinks that Iggy was just a cute little turtle until Iggy comes up close can punches Mario in the face with his clown car causing Mario to scream in pain. Mario declares war now and decides to fight. Iggy's clown car pulls out a cannon from it's mouth and starts shooting Bullet Bills toward Mario and Yoshi.
Mario quickly thinking tells Yoshi to eat all the Bullet Bills which Mario starts punching Yoshi which releases his tongue that grabs and eats the incoming Bullet Bills. Eventually after eating many Bullet Bills Yoshi has fattened up and topples. Iggy seeing this not work decides to pull out a button remote and transform his clown car into a transformer. Upon seeing this Mario goes back to Yoshi for help, but Yoshi said to kill himself instead. As Iggy then starts going towards them Mario started ground pounding Yoshi's stomach which causes him to start shooting the Bullet Bills towards Iggy causing his transformer to blow up among the trees behind them. Mario then starts dancing while Yoshi wishes to die.
Next in World 2: Haunted House, Mario is trying to get Yoshi into the haunted house but Yoshi is seen fighting back not wanting to go into the house. Yoshi then runs away with Mario calling him a scared little a**. In the house, Morton orders the Boos to scare Mario, but it doesn't work. Then, the boos turn into Boolossus, but Mario doesn't think is scary and shows a video of Bowser imagining him and peach kissing. This scares Boolosuss. Morton falls and Mario asks if he wants to see the video, only for Morton to get scared and runs away.
Then in World 3: Caverns, Yoshi is being attacked by bats and spinies. Mario, who was watching from above, tells Yoshi he will save him. Suddenly, a flying question block arrives towards Mario, in which Mario punches the block to get a cape feather power-up. Mario then declare himself a hero and floats down but is stuck on a spiny. Afterwards, Mario and Yoshi encounter Lemmy, who tells them that they will never escape the cavern and ask if he liked the bats and spiny traps. However, as Lemmy continues to talk, Mario then said that he is going to go fishing and grabs out a gun. Mario and Yoshi then sneaks pass Lemmy as Lemmy continues to talk. Lemmy later realizes that Mario and Yoshi ignored him and uses his wand to block the path with a big rock. Lemmy then call them suckers and goes to watch anime. Mario then tells Yoshi to eat the rock, but Yoshi says no and tell Mario to suck his d*** as he left. Mario then paints the rock like a melon and tell Yoshi to come back, to Yoshi's delight. He eats the rock, which gets him fat again. As Lemmy is watching his anime, Mario uses Yoshi to roll out of the caverns, which Lemmy is confused and says "Ah s***!".
In World 4: Sky, Mario punches a flying question block as he and Yoshi find wings which they use to fly. As they fly in the sky, Mario realizes that he can see so many people from there, in which he waves at a red Teletubby and an old man, in which they wave back, before the red Teletubby beat the old man up. Meanwhile, Ludwig arrives and tries to kill Mario and Yoshi using his airship, but the cannons were missing shots and the heavy missles hit a flying koopa troopa, a bird, the shy guy who likes toast, and an airplane. Ludwig then thinks that their defense is too strong and tries charging at them, but Mario and Yoshi find a Star in a question block, which they use and Ludwig is defeated. Mario is confused but then says Na, its probably nothing.
In World 5: Forest of Illusion, Mario sees a spaghetti on a table. He wants it, so Yoshi uses his tongue to grab it. But it was revealed to be a trap and Yoshi's tongue is stuck, causing Yoshi to scream in pain and Mario jumping off him. Mario then crawls away and wonder where they are, but then he sees Luigi in a cage, who beg Mario to save him. However, Mariosays he'll save him later, making Luigi mad and causing him to scream. Then Luigi turns into a giant barney, much to Yoshi's horror. Mario thinks its a bigger Yoshi so he tries to get on, only to get on barney's face. They fall and barney is actually Roy, to Mario's confusion.
In World 6: Underwater, Wendy is taunting Mario and Yoshi with a shark. Mario throws an Amp in the water, electrocuting Wendy and the shark. Wendy, the shark, and a couple dead fishes then float out from the ocean, in which Mario says that he is all done.
In Star World: Rainbow Road, Mario wonders how did he and Yoshi went from a water level to space, in which Yoshi responded that he doesn't know and says that it is a Mario game, making Mario having more sense. Larry then suddenly appears, with Mario asking him if he wants to duel and tell him to get on with it. Larry then was a bit speechless, with Mario telling him he want to get on the Jumping Castle. Larry then tells them he had a race mini game planned in order to race Mario and Yoshi. Mario agreed and the two started to race, with Mario getting a head start. As the race begins, Mario uses the same video he showed to Boolosus to try to distract Larry, but the phone flew out of his hand as a result. Larry then throw a few spinies shell at Mario, but Mario tells Larry that he missed all of them until one of them broke Mario's head. Larry then went ahead of Mario, so Mario tells Yoshi to use his tongue, who grabs Larry's kart. Mario then begins to climb on Yoshi's tongue to try to get Larry, in which both ended up fighting in his kart. Then Larry drove past a question block as they both get an item. Then they aimed their items at each other in which Larry recieved a Rocket Launcher, while Mario got a Banana. Mario then sees the Banana and says that it was a load of s*** as Larry uses the Rocket Launcher to blow up Mario, causing him and Yoshi to be thrown off the course and begins to fall. Larry Koopa is the winner.
Yoshi then says he and Mario won't survive the fall. Mario then thinks and thought of an idea. He moves himself and Yoshi directly over to a different place as Mario reveal that they should be able to land in a place that Mario knows. Meanwhile, Bowser Jr. is jumping on the Jumping Castle, with Bowser asking him if he can come on, since Bowser Jr. has been on the castle for 16 hours straight. Bowser Jr. then says no as he continues bouncing, causing Bowser to throw a temper tantrum. Suddenly, as Mario and Yoshi continues to fall, they caught on fire. Bowser Jr. then realize that Mario and Yoshi is coming out of the sky as they fall on him and the Jumping Castle, causing a small explosion. Yoshi then collapse as Mario realized that they made it. Then Mario realizes that he flattened Bowser Jr. Later, he tells Bowser to get on, in which Bowser agreed. The narrator then said that they bounce for 3 weeks straight and have to go the hospital. Yoshi then says he want to die as the episode ends.