Spine Coaster

Spine Coasters are rideable creatures made of bone used to aid Mario and company to pass through lava pits or poison pools or to cross long gaps. They first appear in New Super Mario Bros. Wii.

New Super Mario Bros. Wii
Spine Coasters appear in World 8-7 from New Super Mario Bros. Wii, a stage that can be unlocked by finding the secret exit in World 8-2. It also appears in multiplayer versus mode. Spine Coasters are the only method of transportation throughout the level, and they often make risky maneuvers, passing through lava geysers and into the lava itself. Players must time their jumps to avoid coming in contact with the lava and losing a life. Spine Coasters can stand the weight of Mario, Luigi, and both Toads on it. However, if all characters perform a simultaneous ground pound, it will fall and they lose a life each.

Super Mario 3D Land
Spine Coasters (here called Bone Roller Coasters ) later appear in Super Mario 3D Land, where they are only found in 2. Their design has changed into a broader, three-dimensional figure. The skull has protruding eye sockets and horns, and its maw is wide and blunt (as opposed to the narrow and pointed maw from the New Super Mario Bros. Wii design), to match with the coaster's wider figure. This alternate design for the skull somewhat resembles the thumb and bucket of an excavator, as well as the skull of a Dry Bones.

New Super Mario Bros. U / New Super Luigi U / New Super Mario Bros. U Deluxe
In New Super Mario Bros. U, Spine Coasters appear in two levels: the Rock-Candy Mines level Thrilling Spine Coaster, a course similar to the world shown in New Super Mario Bros. Mii, and the Superstar Road course, Spine-Tingling Spine Coaster. Spine Coasters and Spine Coaster tracks also appear on the world map, and can be used to travel between Frosted Glacier and Rock-Candy Mines. In New Super Luigi U, besides reprising their role on the world map, Spine Coasters appear in the levels Spine Coaster Stowaways and Spine Coaster Connections.

Spine Coasters reprise the aforementioned roles in New Super Mario Bros. U Deluxe.

Other appearances
Spine Coasters have also appeared in the Wii U demo New Super Mario Bros. Mii shown at E3 2011. One is seen in a dark cavern that is filled with poison, carrying Mario and friends once again.

Trivia

 * The Spine Coaster somewhat resembles a Bone Dragon, but its head is smaller and there are no spikes on its back.
 * Whenever the Spine Coaster goes fast, especially on a slope, it lets out a dinosaur-like roar. The Bone Roller Coasters in Super Mario 3D Land make a different noise.