Volcanic debris

"Careful of the lava! It descends with enough force to punch a hole in the ground. That'll HURT if it hits you!"

- Kersti

Volcanic debris are recurring molten rocks first seen in Mario Party. They are often found falling from the background of volcano-based levels.

Mario Party
Volcanic debris first appears in Bowser's Magma Mountain in Mario Party, where it is launched from a volcano when a player lands on a Happening Space. It changes the Blue Spaces into Red Spaces for two turns.

Mario Kart: Super Circuit
Volcanic debris (under the name of Lava Boulders in this game) appears in Mario Kart: Super Circuit, where the volcanoes in the background of Lakeside Park launch it onto the track. The racers are burned if they run into it.

Mario Kart Wii
In Mario Kart Wii, volcanic debris appears on Grumble Volcano, where it is fired from volcanoes, and spins out racers that crash into it. It remains on the ground for some time after it lands.

Mario Kart 8 / Mario Kart 8 Deluxe
Volcanic debris reappears in Mario Kart 8 and Mario Kart 8 Deluxe, where it returns in Grumble Volcano. It moves slower than in Mario Kart Wii when it is falling to the ground, and the flames are also smaller when they make impact with the ground.

Mario Kart Tour
Lava Balls return on the Mario Kart Tour rendition of GBA Lakeside Park. They tumble down the trails and slopes of the course, similarly to rolling rocks, while also producing craters in the spots they land which drivers can perform Jump Boosts from. The Lava Balls themselves cause drivers to spin out on contact, but can be destroyed by hitting them with a Bowser's Shell, Bob-omb, Super Horn, Giga Bob-omb, or Super Bell, or by ramming into them while under the effects of a Frenzy, Mega Mushroom, Bullet Bill, or Super Star. When a player destroys a Lava Ball, they receive bonus points.

Donkey Kong Jungle Beat
In Donkey Kong Jungle Beat, volcanic debris first appears at the end of Sweet Paradise, a sky-themed level, though later only appears in volcano levels. They fall diagonally from the top of the screen before exploding.

Donkey Kong Country: Tropical Freeze
In Donkey Kong Country: Tropical Freeze, volcanic debris makes an appearance in the level Mountain Mania, where after a statue of an owl gets split, volcanic debris starts erupting from the resulting fissure, destroying many of the following bridge segments.

New Super Mario Bros.
Volcanic debris reappears 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, and hurt Mario or Luigi if they touch one. They can be destroyed with a Super Star.

New Super Mario Bros. Wii
The rocks later appear in New Super Mario Bros. Wii, and is mostly found in World 8-1 alongside hazardous ash, Buzzy Beetles 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.

New Super Mario Bros. 2
Volcanic debris appears in New Super Mario Bros. 2, in which its role is the same as in its previous appearance. It is only found in World 6-1. Small volcanic debris drops one coin when it is destroyed by Gold Mario, while large volcanic debris drops three coins.

New Super Mario Bros. U / New Super Luigi U
In New Super Mario Bros. U and New Super Luigi U, volcanic debris was replaced by Meteors and Bowser's Fireballs, though they have the same behavior.

Super Mario 3D World / Super Mario 3D World + Bowser's Fury
Volcanic debris also appears in Super Mario 3D World and Super Mario 3D World + Bowser's Fury, 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 the pink Hisstocrat.

Paper Mario: Sticker Star
In Paper Mario: Sticker Star, volcanic debris is only found in one level, Rugged Road. The molten rocks can still hurt Mario if he touches them, but now they can also harm him if he gets caught in the spot where they land for about one second. In addition, the rocks also home in on Mario.

Paper Mario: Color Splash
Volcanic debris appears in Paper Mario: Color Splash in the level Kiwano Temple. It appears at the end of the level, where it jumps out of the lava and hovers over the platform Mario and Huey are on. If Mario touches it, he will take 8 HP of damage.

Mario & Luigi: Dream Team
Volcanic debris also appears in Mario & Luigi: Dream Team, where it is used as a weapon for Mount Pajamaja.

Captain Toad: Treasure Tracker
Volcanic debris reappear in Captain Toad: Treasure Tracker and its Nintendo Switch and Nintendo 3DS ports. It rains down during the Draggadon and Gold Draggadon boss battles.