Gaijin Goombah is a YouTuber. He has had several cameos in The Lonely Goomba videos. He makes top tens, reviews, and theories.
The first appearance of Gaijin Goombah in The Lonely Goomba's videos was the Super Mario Land: Revisitied video. When Goomba begins insulting the Japanese style, Gaijin appears. When he suddenly leaves, Goomba calls him a douche.
Gaijin reappears in the Two Part Goemon series. In Part 1, he tries to stop Goomba from putting a purple game cartridge in the Game Boy Advance, but fails, causing the Great & Power Gamey to appear. If Goomba and Gaijin don't finish the game by sunset they will be stars of Goomba Got Back 2, which will ruin their reputation, so they play. When Goomba and Gaijin "finish" World 1 (but actually fail the boss), Goomba calls Gamey to check. After he realizes he didn't beat the game, Gaijin escapes, bringing Goomba with him. In Part 2, they end up in Gaijin's home and continue the game. They eventually have to escape to World 1-2 (Underground) so Gamey doesn't find them. However, the Game Boy's batteries are about to die, so they have to return to World 1-1, only to find the batteries Goomba has are AAA batteries. Before they can finish the game, Gaijin is trapped inside the Goomba Got Back 2 game, causing Goomba to activate his ninja state and beat the game. Gaijin reappears and he and Goomba make their wishes. While Goomba wishes for a Game Boy, Gaijin wishes to go back home and be with his family, and disappears.