Dry Bowser

Dry Bowser is a bonewyrm version 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.

Unlike previous occasions, 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. Dry Bowser has an extremely horrifying howl combined with the rattling of bones from his entire body. This can specially be heard in Mario & Sonic at the Olympic Winter Games when the player faces him in Ice Hockey.

History
New Super Mario Bros.

In New Super Mario Bros., to defeat Dry Bowser, Mario must dodge his attacks, which include breathing small flames and throwing his own bones, and wait for him to make a high jump. Mario must then run under Dry Bowser and hit the Skull Switch, destroying the bridge and throwing him into a very deep pit; when he finally hits the ground, his whole body falls apart. An experienced player, however, may be able to jump over Bowser at the very start of the fight to reach the switch, after which Bowser "runs" after Mario to stop him. 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 6-8 of Super Mario Bros.; however, in that game he threw hammers instead of bones. He is also immune to fireballs.

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.

However Dry Bowser does not appear in this game's sequel, New Super Mario Bros. Wii.

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 was the only CPU opponent in the second Competition of March 2009, where he attacked the player by firing fireballs at him/her throughout the race in the Mario Kart 64 version of Bowser's Castle.

Dry Bowser features a good off-road (tied with Toadette) and mini-turbo (tied with Wario, Koopa Troopa, and Dry Bones) bonus, which makes vehicles like the Flame Flyer and Phantom perform a bit better off the track, along with getting a slightly better mini-turbo after a drift.

Appearances in Other Games
Dry Bowser appears in Mario Kart Wii as a heavyweight character. According to early leakers of the game, he is unlocked by obtaining a Rank 1 Star in every 150cc Wii Grand Prix course.

Trivia
Bowser has previously been seen falling in lava in Super Mario Bros. and The Lost Levels without showing his apparent demise. In Super Mario 64, however, Bowser wasn't affected when falling in lava. Additionally, Super Mario RPG: Legend of the Seven Stars, Bowser comments that he loves the smell of lava in his castle.