Kinkotsuman is a character in Yudetamago's manga and anime series Kinnikuman and its sequel Kinnikuman Nisei. His name is changed to Skullduggery in Ultimate Muscle.

Real Name: Sharekoube (シャレコウベ)
Classification: Gokuaku Chojin
Homeland: Planet Dokuro
Age: 25, 70 (Nisei)
Height: 178 cm
Weight: 80 kg
Chojin Kyodo: 200,000 Power
Favorite Techniques: Perpendicular Back Drop, Kinkotsu Headbutt, Kinkotsu DDT
Tag Teams: Monster Master/Student Combo
First Appearance: Manga Chapter 18, Anime Episode 1

Kinkotsuman is an alien who has come from Dokuro-sei (ドクロ星, Planet Skull) in order to conquer Earth. He has the character for bone (骨) on his forehead. He was Kinnikuman's nemesis in the early chapters and was just as silly and stupid as his rival. After his loss to Kinnikuman he reappears with Iwao as his sidekick, and from then on they plot schemes in order to defeat Kinnikuman.

In the original manga he disappears after the series switches to just wrestling, but in the anime he and Iwao appear alongside Detective Gobugari as members of the Seigi Choujin's cheering party for the remainder of the series.

(Source: Kinnikuman Wiki)