From the Super Mario Wiki
World 2 is the second world of the game Yume Kōjō: Doki Doki Panic, and was also featured in the game Super Mario Bros. 2. The world has a desert and pyramid theme to it, which is later revisited in World 6. It is in this world that the player meets for the first time the Cobrat Pokey and Panser enemies, as well as their first boss fight against the red Birdo the can spit fireballs as well as eggs. The main boss of the world, fought at the end of World 2-3, is Tryclyde, the three-headed snake.