3DS Piranha Plant Slide

Piranha Plant Slide (known as Piranha Plant Pipeway in the British English version) is the first course of the Star Cup in Mario Kart 7. It is based on the underground levels of Super Mario Bros., and appears to take place in a sewer. It consists of floating blocks, three Goombas (which are blue underground, as in the original game, albeit only in 7), and Piranha Plants. The music for the course contains parts of the Ground Theme and Underground Theme from Super Mario Bros.

The course returns as the second course of the Lightning Cup in Mario Kart 8 and Mario Kart 8 Deluxe, and also returns in Mario Kart Tour, debuting in the Piranha Plant Tour.

Course layout
The start of the track begins at a castle, from which players drive down three water slides that lead into a pipe with a sideaways and top entrance in the same fashion as World 1-2 in Super Mario Bros. The track is mainly underground. It has flowing water that can cause the player to speed up when driven on, similar to Koopa Cape from Mario Kart Wii. There is a huge Piranha Plant in the middle of the road, which causes the track to split for a bit. After passing the Piranha Plant, two Goombas are encountered. Both are blue, similar to the underground ones in Super Mario Bros. A huge jump right after the Goombas leads the player to regular ground. Players also have the option to jump and drive on rows of floating bricks and collect Coins on them before landing on the ground. A few pipes on the ground provide jumps for the player in the turns afterwards, which form a zigzag. Soon, the player must go down a huge pipe into a section that is underwater. Some pipes generate currents that allow for players to be blasted to higher ledges. Another Piranha Plant blocks the path at the end of the tunnel, causing players to have to maneuver around it, though players can drive above it using the current-producing pipes. Then, players drive up a ramp which takes them above ground to a fortress with three Drain Pipes that the player must avoid. They will land on a grassy area with walls, Horsetails, and bushes heavily resembling the Super Mario Bros. backgrounds. Some boards shaped like Goombas and bushes are placed in the road, too, and there are gaps in the fences where players can use a Mushroom to cut through the grass before the finish line.

In Mario Kart 7, the bushes and clouds that appear on this course share a model, only with different textures and shading. This is a reference to Super Mario Bros., in which bushes and clouds shared the same sprite, albeit recolored.

Mario Kart 8 / Mario Kart 8 Deluxe
Piranha Plant Slide makes its classic course debut in Mario Kart 8 and Mario Kart 8 Deluxe as the second race of the Lightning Cup. Compared to the other 3DS courses in the game, the track received many notable changes. Its aesthetic has been altered to resemble Super Mario Bros. less, in line with the more realistic artstyle of 8 and 8 Deluxe. The underwater version of the music has been removed. The starting banner, though still castle-themed, has been expanded to resemble the exterior of the larger castles, such as the one found at World 1-3 of Super Mario Bros., with towers added to the expanded walls on the side, replacing the flagpoles. The banner and towers also serve as stands for several Toads and Koopa Paratroopas.

The biggest change done to the course is the alteration of the underwater section. The chute that enters the water now goes straight down and is wider, longer, and has three slides akin to the opening of the track, instead of being a small spherical hole in the wall. Several trick ramps while heading down the chute replace the trickable pipes found in the original version of the track. The chute and the underwater section are also now an anti-gravity segment, with the track going down and then sweeping upward towards the glide ramp through a large tank populated with Cheep Cheeps, rather than through a closed tube. This results in a much steeper Glide Ramp. The ledge reachable by way of a current has also been repositioned to rest in the center of the track, instead of along the right side; it now allows racers to jump over the Piranha Plant prior to the Glide Ramp.

The three slides at the start/finish line have a ramp added at the end, allowing racers to perform tricks on them. The Star Cup sign at the entrance to the tunnel has also been removed, due to it being a retro track. In addition, the first of the two grass shortcuts during the last stretch has been removed, likely due to it being easily done without a Mushroom via gliding over it in Mario Kart 7. However, gliding over it outside of 200cc is impossible without a Mushroom due to the gliding section being made much steeper; in 200cc, the speed increase allows racers to glide over the top of the castle wall and beyond. Small Piranha Plants from have been added throughout the aboveground section of the course.

Mario Kart Tour
Piranha Plant Slide returns in Mario Kart Tour in the Piranha Plant Tour. Like with 3DS Neo Bowser City, it mostly uses its appearance from Mario Kart 7 as opposed to Mario Kart 8. Because of this, the starting line has been reverted back to the version seen in Mario Kart 7, albeit with the castle having a more straight orientation compared to its previous appearances. The Goombas, however, retain their normal coloration, like in Mario Kart 8. The underwater section has also been reverted to its original appearance and layout as a confined tunnel with trickable pipes along the ground. However, the final section retains its adjusted layout that removed a shortcut from Mario Kart 7. Additionally, one of the Empty Block rows has been removed during the underground section, likely to better suit the more limited controls. The water that comes from the pipes towards the end of the course no longer acts as an obstacle, and can be glided through with ease. The underwater version of the music returns.

As with other courses in the game, Piranha Plant Slide has a reverse variant, a trick variant and a reverse/trick variant, referred to as Piranha Plant Slide R, Piranha Plant Slide T and Piranha Plant Slide R/T respectively. The first two debuted alongside the course, while the R/T variant debuted in the 2023 New Year's Tour.

For this course's tour appearances, see List of 3DS Piranha Plant Slide tour appearances in Mario Kart Tour.

Mario Kart 8 Original Soundtrack liner notes
"Compared to this course's Mario Kart 7 incarnation, the amount of water flowing up and the size of the pipes have really been scaled up, and so even though it retains the 8-bit atmosphere, it's become a really dramatic course. We wanted to reflect this in the background music by making it more sweeping in scale and arranging it more dynamically."

Trivia

 * In the Mario Kart Tour appearance of Piranha Plant Slide R and R/T, if the course's intro is skipped while overlooking the underwater section, the underwater variant of the course's music will play when the race begins. Exiting the underwater section or restarting the race when this happens will switch back to the regular music instead.