Dry Bowser is a video game character from Mario Kart Wii who is a skeletal version of Bowser. But it will only be available if you can unlock it. Here is the wikiHow for unlocking Dry Bowser on Mario Kart Wii.
Steps

Step 1. Select your license

Step 2. Select single player mode

Step 3. Select Grand Prix 150 cc

Step 4. Choose a character

Step 5. Choose your kart or bike

Step 6. Earn one or more stars in all 150cc Wii races
Advice
- Use a kart / bike with good acceleration.
- Use the shortcut as needed.
- Toddlers (Peach, Mario, Luigi, or Daisy) Rosalina and other small characters are perfect for speeding up with a bullet bike or Mini Beast.
- Try to win all races.
- Try not to get hit.
- Be the first.
Warnings
- Do not throw the spiky shells (blue) if you are in first or second place (they will hit you even if you throw them).
- Try to avoid red and green shells by throwing bananas, bombs, or other shells at them.
- try not to die. (Or fall)