World 8 is the eighth world in New Super Mario Bros. that Mario and Luigi venture through. In this world, Bowser Jr. is a mini-boss two times and a boss one time in Bowser's Castle. This world also features many lava-like levels and Bowser's Castle. The other bosses in this world is Dry Bowser and Bowser. It is a volcanic bandland and it has poisonous red cloud, even though Mario cannot touch them and they cause no harm. Lavas kill Mario instantly. In the small purple castle, if the Mario killed Dry Bowser, a new music can be heard which is sometimes interesting.