Dry Bowser

Dry Bowser is an undead, skeletal form of Bowser, debuting in New Super Mario Bros. Dry Bowser was accidentally born in New Super Mario Bros's first castle, when a short fight with Bowser ended with Bowser being dropped into a pit filled with lava. The lava reduced the once-mighty king to a skeleton, leaving his son, Bowser Jr., temporarily in command of the Koopa Troop. He is then fought in the first castle in World 8. He makes an appearance as a unlockable driver in Mario Kart Wii, classified as a Large-sized character.

New Super Mario Bros.
In New Super Mario Bros., to defeat the skeletal monster, Mario must dodge Bowser's attacks, which include breathing small flames and throwing his own bones, and wait for Bowser to make a high jump. Mario must then run under Bowser and hit the Skull Switch, destroying the bridge and throwing Bowser into a very deep pit. If Mario is in Shell Mario form, he can defeat him by performing the Shell Dash against him three times. As Mega Mario one stomp is enough. A very simple way is to at least have a Super Mushroom then run straight through him and hit the switch. This battle is very similar to the battles against Bowser in worlds 5-8 of Super Mario Bros.; however, in that game he threw hammers instead of bones.

At the final battle of the game, the remains of Dry Bowser were thrown in a cauldron (the contents of which were unknown, but they were most certainly magical) which turns Dry Bowser back into his original form, except much larger, as if he had used a Mega Mushroom.

Mario Kart Wii
Dry Bowser makes his first playable appearance in Mario Kart Wii. He is a Large-sized driver along with his living counterpart, Bowser. However, it seems more reasonable that Dry Bowser would be a lower weight class, as he lacks all matter other than bones. It is likely that his size that puts him in the class, seeing that weight doesn't always matter when it comes to the large karts (for example, Waluigi and Rosalina also look as if they should be in a lower weight class, but are too tall to fit in the medium size karts). He has a more terrifying roar than Bowser in this game, mixed in with several bone rattling sounds, which make up his sound effects throughout the game. He can be unlocked by beating all new cups on 150cc with at least 1 star ranking.

Dry Bowser has a good off-road and mini-turbo bonus, which makes vehicles like the Flame Flyer and Phantom perform a bit better off-road along with getting a slightly better mini-turbo after a drift.

Personality
Dry Bowser's personality did not change much from his living counterpart, Bowser. He is a cruel and ruthless villain, almost more so then his living counterpart, as shown by his more terrifying roar. This may be because his transformation pushed his anger and hatred of Mario to the extremes, possibly completely corrupting himself.

Physical Description
Appearance wise, Dry Bowser's main change via the transformation, is his skeletal body. Opposed to Bowser's Green Shell, Dry Bowser's Shell is Dark Red. Also, as opposed to Bowser's Spiked black Collars, Dry Bowser has Spiked red Collars. Another main difference is that while Bowser has a fiery red mane, Dry Bowser has a fiery red ponytail, more similar to Bowser Jr.

Mario
Dry Bowser's arch nemesis and main enemy, no different from when he is alive. Dry Bowser and Mario have had a small amount of antagonism, as seen in New Super Mario Bros. Dry Bowser fought fiercely against Mario, as he was responsible for Dry Bowser's creation. Mario defeated Dry Bowser, who was later revived by Bowser Jr. More recently, they have competed against each other in Mario Kart Wii.

Bowser Jr.
Dry Bowser's son, and closest ally. Bowser Jr. and Dry Bowser have only briefly been seen together, though it is likely they still share the same relationship from when Dry Bowser was alive. Bowser Jr. was also the one who revived Dry Bowser from his Dry Bones state.

Mario Kart Wii

 * Size: Large
 * Stats:
 * Acceleration:*/***
 * Top Speed:***/***
 * Off-Road:*/***
 * Site Bio: "If the King of the Koopas wasn't scary enough already, his appearance as a surly skeleton should have the other drivers shaken in their seats!."
 * Prima Guide Bio: ''After a little dip in lava, Dry Bowser, King of the Dry Bones, returns invincible! Fortunately though, he's driving the same karts and bikes as everyone else!"
 * Actual Bonuses
 * Off-Road: +2
 * Mini-Turbo: +2

Trivia

 * Stangely, Dry Bowser's Japanese name (Honekuppa) is actually based on Dull Bones' Japanese name (Honenoko), Instead of Dry Bones'.
 * Dry Bowser was one of the only playable characters from Mario Kart Wii that never appeared in Mario Super Sluggers (Rosalina is another one).