Eiichiro Oda stated that Gaimon was his favorite character in an interview from One Piece Color Walk 1 (published in 2001).
Gaimon has a green afro hairstyle, a black beard, a chubby face and a big mouth. He has been stuck inside a treasure chest for twenty-two years, and his body’s shape has grown accustomed to it overtime, making it virtually impossible for him to get out.
Gaimon before he got trapped in the treasure chest:
Gaimon and Sarfunkel after the timeskip:
His pairing with Sarfunkel is a spoonerism of the singing group Simon and Garfunkel.