Gastly will be level 23. Gastly is, put kindly, a complete asshole. It likes to sneak up on people and startle them, it has atrocious breath which it likes to exhale in the direction of unsuspecting people, and cast inappropriately-shaped shadows onto walls.

It is also overly fond of sweets, and can be coaxed into good behavior if sweets are withheld although it might throw a mighty big tantrum the first few times.