Wii Grumble Volcano

Grumble Volcano is the last course in the Star Cup of Mario Kart Wii. It takes place in a volcanic area covered with lava, specifically the crater of a due to the lack of water around the volcanoes. The course features many jumps and moving platforms, as well as many sharp corners. At certain times, sections of the track will crumble away into the lava, making the road smaller and harder to drive around. The track's theme is very similar to that of World 8 in New Super Mario Bros. It reappears as a retro track in Mario Kart 8 and Mario Kart 8 Deluxe as the third course in the Lightning Cup.

Mario Kart Wii
The course takes place inside and around a volcano surrounded by lava. The first part of the track takes place inside the volcano with sections of the track that fall into the lava as the race progresses (except for one section that sinks during the countdown of the race). Outside, the volcano erupts Volcanic debris, which causes the ground nearby to shake and the area where it lands to temporarily set on fire, which will spin out the racers if they touch it. In the part where the track splits into two paths, there are Fire Snakes that come out of Warp Pipes and jump around, causing the player to spin out on contact. ? Blocks and Brick Blocks are found lodged in the rocks as part of the scenery.

Course layout
At the beginning of the race, the track is straight. However, parts of this section will fall into the lava as the race progresses and cause more places for players to fall into the lava. Lava Geysers may occasionally spout in these areas. The track then enters the volcano and makes a turn, which will also crumble as the race continues, before approaching a moving platform, which a player can perform a Trick from. This leads into another tunnel with a tighter upper route and a wider lower route, both of which have Item Boxes, that curve right and then left before leaving the volcano and approaching a pair of moving platforms, which also allow the player to perform tricks.

From these platforms there are two roads: the right, which has a ramp with a Dash Panel on it, and the left, which has Item Boxes. After the roads meet again the player encounters Volcanic debris, which can cause the player to spin out. During this section, pieces of land will crumble and begin to sink into the lava. The path then splits again, with a Dash Panel and ramp now on the left and no item boxes on the right. The paths then meet and come to a small ramp which allows players to perform tricks.

After the ramp, the path splits again with the right side taking a lower route which eventually turns left to a pair of ramps which the player can perform tricks from, and the left taking a higher route to a ramp with a Dash Panel. Both routes have crumbling sections of track and have pipes with Fire Snakes, as well as falling Volcanic Debris. The routes then meet and approach the starting line for the next lap. This time, however, crumbling pieces of land are much more evident than they were in the first lap.

Shortcuts

 * Near the starting line is a rock that can be reached with a mushroom and performing a wheelie at the starting line or by performing a trick off the ramp before the finish line in a direction towards the rock. Once on the rock, the course can be completed by driving around the rock. The player must be careful as the rock will start to crumble at 53 seconds, and sink at 1:05. This glitch was removed in Mario Kart 8 as it does not use a checkpoint system to determine if the lap will count like Mario Kart Wii does; besides that, the slopes of the rock are so steep that players will simply slide off.
 * After the cave and past the moving platforms is a rock to the right side of the raised section of the track. In the Mario Kart Wii version, it is possible to drive on the rock formation by using a mushroom to reach the right side of the forked road. The rock will sink 1:35 seconds into the race, however, the player can still have Lakitu bring them to the right side of the fork with the use of a mushroom and a wheelie or well-timed hop if they hit the edge and fall into the lava.
 * Near the end of the Mario Kart 8 version of the course, at the right side of the fork, there is a pipe. Beside the pipe is small part that the player can do a trick off. In laps 1 and 2, there is a rock blocking the shortcut, but at the start of lap 3, it will sink into the lava, letting the player use it on lap 3. (This shortcut is also possible in Mario Kart Wii but there is no trickable ramp and it takes two Mushrooms. It is possible with one, though it is extremely precise.)

Tournaments
The first tournament of June 2009 took place at this course. Players competed in a time trial race, but they had to race the track backwards. To start the time trial, players received a set of Triple Mushrooms. This tournament was later repeated as the second tournament of May 2011, the second tournament of August 2012, and the first tournament of November 2013, though with a "Karts only" restriction.

Mario Kart 8 / Mario Kart 8 Deluxe
Grumble Volcano returns as a retro course in Mario Kart 8 and Mario Kart 8 Deluxe as the third track in the Lightning Cup. The volcano that the players drive through as well as the volcanoes in the background now have lava running down them. The course itself maintains its layout from the original, though both the first platform after the cave and the jump from the uphill left path now have Glide Ramps. Volcanic debris falls more slowly than in the original course, the crumbling pieces of road crumble and sink much quicker (with an additional sinking piece of land added in the Volcanic Debris section of the course), and the course banner has been changed, now resembling a slightly deteriorated structure with torches added. The music also remains the same, similar to 3DS DK Jungle and 3DS Neo Bowser City, but has been given an echo effect.

Staff ghost
In Mario Kart Wii, the staff ghost for this track is Dry Bowser in the Offroader. In Mario Kart 8, the staff ghost is Roy on the Badwagon, with a time of 2:18.305. In Mario Kart 8 Deluxe's 200cc mode, the staff ghost is Morton with a time of 1:44.284.

Mario Kart Wii

 * European website bio: "With deep lava awaiting anyone who strays off the track and flaming fireballs littering your path, Grumble Volcano will undo all your previous hard work in the Star Cup if you aren't at the top of your game."
 * Trading card bio: "The racing can really heat up when battling it out at Grumble Volcano. Lakitu is always busy fishing racers out of the lava beds that line this course. There are many opportunities for mishaps here so watch who you're bumping into. And be sure to watch out for the sections of track that fall away."

Mario Kart 8 Original Soundtrack liner notes
"This is a remastered version of the Mario Kart Wii track. With all its boiling lava and cracking, sinking surfaces, there's something slightly bleak and downbeat about this course. We wanted to get this across in the music, but without making the atmosphere too heavy."

Mario Kart 8 / Mario Kart 8 Deluxe

 * Bullet Bill Speed Trial (Signs)
 * Morton Construction (Signs)