Wart

Wart is a character and the main villain of Super Mario Bros. 2. In the game Wart had some how entered Subcon, the land of dreams and had begun a conquest of it. Enslaving Subcon's inhabitants to be his soldiers and also creating monsters using a device called the Nightmare Machine Wart's victory was assured. In a desperate attempt to save their world, Subcon's original inhabitants, fairies also called Subcons, contacted the great hero Mario in his sleep to ask for his help. They also gave him a hint to beat Wart. The clue was Wart did not like Vegetables. Mario believing the message to be nothing more than a dream dismissed it and later that day went on a picnic to the park with Luigi, Toad and Princess Toadstool. It was there Mario discovered a door in cave which when the group went through brought them to Subcon.

Mario realizing that the call for help was real convinced the others to help liberate Subcon. After a long journey in which Mario and co. defeated Wart's generals, Triclyde, Mouser, Birdo, Fryguy, Clawgrip, and Robirdo the gang eventually encountered Wart himself. Engaging Wart in combat Mario managed to defeat him by throwing vegetables (which Wart is allergic to) into his mouth. With Wart defeated Subcon was free and after the victory celebration Mario woke up in his bed and was left to ponder if the events that transpired had really happened or if they were all just a dream...

Other Appearances
Wart made a surprising appearance in the game Legend of Zelda: Link's Awakening. Though some people question his appearance in the game it seems to be Wart (who in the game is called Mamu which is Wart's japanese name). Wart was actually helpful to Link, teaching him a new song to play on his ocarina. Link's Awakening like Super Mario Bros 2 supposedly took place in a dream world. A monster similar to Wart (large, frog-like, shoots bubbles) also appeared in Legend of Zelda: Majora's Mask.

A frog named Wart Jr. appeared in the game Animal Crossing. He is a nice neighbor who is sometimes prone to grumpiness. In Animal Crossing: Wild World Wart Jr. once mentioned having plans to conquer the world.

Wart was mentioned in Mario Superstar Baseball however never seen.

Appearances in Other Media
Wart made an appearance in a Mario comic Cloud Burst. In the comic Wart disguised as a bed salesman abducts The King and also tries to flood the Mushroom Kingdom. Despite this being his only comic appearance Mario mentions that Wart seems to have made a hobby out of kidnapping The King (similar to Bowser and the Princess). Wart looked more like a crocodile than a frog in the comic.

Wart made an appearance in the Mario Adventure Book Doors to Doom where he ended up helping the Mario Bros. He was also, oddly dressed like a skateboarder.

Oddly, Wart appears in reels B and C in a Master-view toy released during the run of the Super Mario Bros. Super Show. Despite being labeled as "King Koopa" the character in the Master-view reels is obviously Wart.