Roger the Potted Ghost

Roger the Potted Ghost is a boss character from Super Mario World 2: Yoshi's Island and is located in The Potted Ghost's Castle, the castle of World 2. Roger starts out as a lifeless pot, but is transformed by Kamek's magic into a large ghost when the player enters the boss room. He is the only inanimate object that Kamek transforms into a boss. His face is the same as those of Dangling Ghosts and Caged Ghosts, and like them, he is amorphous.

To defeat him, Blue Yoshi has to push Roger and his pot over the right edge of the platform in the same manner as pushing a regular pot. This process is complicated by two green Shy Guys that slowly push Roger in the opposite direction. Throughout the battle, Roger can lunge at Blue Yoshi, knocking him away. He also breathes blue flames which home in, forcing the blue dinosaur to stop pushing and get out of the way to avoid taking a hit. When Roger is pushed far enough, the Shy Guys topple over the edge and do not return, allowing Blue Yoshi to push him the final distance without facing resistance from them.

In Yoshi's Island DS, he makes a cameo in the game's introduction, which briefly shows some of the bosses from Yoshi's Island. Additionally, there are enemies called Potted Ghosts. They look vaguely similar to Roger, but are smaller and less malevolent.

In Super Smash Bros. Ultimate, Roger the Potted Ghost appears as a support spirit which grants resistance against strong winds. It is obtainable by winning his spirit battle or summoning it with the spirits of Shy Guy and Boo Mario.

Trivia

 * The blue flames he shoots are based on the hitodama, a phantasmagoric phenomenon in the Japanese folklore which is said to be the souls of the dead.
 * Some stones are seen when he is pushed off the platform, implying that he falls through the floor.