World 2 (Super Mario Bros. 2)

World 2 is the second world of the game 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, egg and fireball-spitting version of Birdo. The main boss of the world, fought at the end of World 2-3, is Tryclyde, the three-headed snake.

World 2-3
If the player plays as Luigi, there is a cave right at the beginning of the level, that only Luigi can jump high enough to get to, that leads to a magic potion and a bunch of coins.