Roger the Potted Ghost

Roger the Potted Ghost, or simply The Potted Ghost or Potted Ghost, is the second boss of Super Mario World 2: Yoshi's Island. He 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.

Super Mario World 2: Yoshi's Island

 * Official Nintendo Player's Guide: Spirits like Bigger Boo and Roger haunt the forts and castles, clinging to rugged mountainsides in World 2. Roger looks mean and has frightfully bad breath, but isn't exactly fast on his feet. In fact, he has no feet. He has to rely on two Shy-Guys to push him around. Since he didn't let them go out for Trick-or-Treat last year, their team spirit is low.
 * Super Power Club Cards bio:
 * Description: Aladdin would never rub this pot, because the genie inside has has a mean streak a mile wide! He doesn't get around much--his only means of transportation is two Shy Guys.
 * Favorite Saying: "Faster, you fools, faster!"
 * How to Beat Him: Push him until he falls off the edge to the right. Avoid the blue fireballs he shoots at you. Keep pushing, because the little Shy Guys are keeping up the pressure, too!
 * Shogakukan guide: つぼから煙のように現れる. ヨッシーをはじきとばしたり、青い炎を吐いたりするが、つぼから出られないのが悲しいサガ. (It appears like smoke from a jar. It can repel Yoshi and spit blue flames, but it is a sad fact that it cannot get out of its jar.)

Yoshi's Island: Super Mario Advance 3
(The boss of World 2-8. It appears like smoke from a jar, tries to knock Yoshi away, and attacks with blue flames. Push the pressure point to drop him from the platform.)
 * Shogakukan guide: ワールド2-8のボス. ツボからけむりのように現れ、ヨッシーをはじき飛ばそうとしたり、青い炎で攻擊する. ツボを押して、足場から落としてしまおう.

Trivia

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