Volcanic debris

is molten rocks seen falling from the background of volcano-based levels.

It first appears in Lakeside Park in Mario Kart: Super Circuit where the rocks are launched by the volcanoes in the background. They land and remain on the track for some time, and if a racer comes in contact with it, they will be burned.

Volcanic Debris later appears 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, not to mention hurting Mario or Luigi if they touch one.

Volcanic Debris reappears in New Super Mario Bros. Wii, and is mostly found in World 8-1 alongside drifting poisonous clouds and rising lava spouts. Larger debris also appears, and can plow through several blocks before landing, in addition to taking up more space. Some Volcanic Debris also appears at the beginning of World 8-2.

Volcanic Debris appears in New Super Mario Bros. 2, in which its role is the same as in its previous appearance. It's only found in World 6-1.

In New Super Mario Bros. U, Volcanic Debris was replaced by Meteors and Bowser's Fireballs, though they are used in the same way.

Volcanic Debris also appears in Super Mario 3D World, with an appearance similar to Bowser's Fireballs in New Super Mario Bros. U. In addition to falling from above, it now creates a lava puddle upon landing. It only appears in The Great Tower of Bowser Land, being expelled by a volcano in the background, and in Hisstocrat Returns and Boss Blitz, in which it is generated by Queen Hisstocrat.

In Paper Mario: Sticker Star, Volcanic Debris is referred to as "meteors" and is only found in one level, Rugged Road. It can still hurt Mario if he touches them, but now it can also harm him if he gets caught in the spot where the debris lands for about one second. In addition, the meteors also home in on Mario. Volcanic Debris reappear in Captain Toad: Treasure Tracker. It rains down during the Draggadon and Gold Draggadons boss battles.

Volcanic Debris also appears in the Mario Kart series. In Mario Kart Wii and Mario Kart 8, Volcanic Debris appears on Grumble Volcano, being fired out of volcanoes and spinning out racers that crash into it. It also remains on the track for some time after landing. In Mario Kart 8, it moves more slowly when falling toward the ground.

Volcanic Debris also appear in Mario & Luigi: Dream Team, where they are used as a weapon for Mount Pajamaja.