Gooper Blooper is a boss that first appeared in Super Mario Sunshine. In this game, he had to be fought three times; twice in Rico Harbor and once in Noki Bay. He has since made other cameo appearances in the Mario franchise. In SMG4's videos, he appeared in "The Pirate Plumbers", Mario Simulator Interactive! (500k Subscribers), and SMG4: Stupid Mario Sunshine.
In The Pirate Plumbers, he was a giant squid who attacks Mario, Luigi, Ben, and Lardbutt by lifting the boat up into the air, which results in Mario, Luigi and Lardbutt standing on the sides of the boat. Mario attempts to kill him with all of the ammo he has, but he cannot be defeated because he is impenetrable from the outside. When he sees Ben, he shoots a blooper out, which Ben figures out is his pet.
After the blooper falls back to Gooper Blooper, Ben gets mad and escapes from the rope, entering Gooper Blooper. The result is the defeat of the giant squid when his eyes become purple with an X through each of them, and he suddenly drops the ship. At the end of the blooper, the owner of the house Luigi and Mario went to in order to unclog the toilet finds the dead giant squid on top of the house, which suggests Mario and Luigi decided to place the corpse on the roof of the house.
In Mario Simulator Interactive! (500k Subscribers), Gooper Blooper appears as a boss to the pirates as soon as their ship enters Bowser's Evil Liar, causing everyone on the ship goes wild, in which the blooper says "I just wanted to be your friend!"
The viewer is then given two choices, to use a picture of Waluigi or the Waluigi Launcher.
At the end of the simulator, when the player beats the game, Gooper Blooper can be seen applauding for the player's victory.
In SMG4: Stupid Mario Sunshine, he appears on the beach. When Mario saw him, he thought that it's anb animal that end up with a wine cork in the mouth because of pollution. Mario helped him by taking out the wine cork. Gooper Blooper thanks him, but when Mario continues onward, he starts spitting ink everywhere.