Volcanic debris

Raining Debris are molten rocks falling from the background. They only appear in World 8-8 of New Super Mario Bros., which is a level with many Kab-ombs. These rocks destroy blocks and set off the fuses on Kab-ombs. If Mario uses a Mega Mushroom to grow big while these are in the area, he will go back to regular size. The player can only get one of the three Star Coins without the raining debris. If one hits Mario, Mario will be downgraded.

Raining Debris reappear in New Super Mario Bros. Wii in World 8-1. They act like in New Super Mario Bros.. In this game, they are much harder to dodge as Mario has to jump through a lava filled land with sometimes small platforms to jump on, rising lava spouts that block the way if Mario doesn't have the Propeller Suit and a cloud of hot ashes on the left that chases and defeats him instantly on contact. They can also help Mario and Co. get a Star Coin at the end of the level if they are small or alone as it's trapped in a series of breakable blocks. They can also cause a Star Coin to fall in the lava if the block that it landed on after a POW Block has been used, gets destroyed. If this happens, it gets impossible to collect all the Star Coins in this level without starting over.