Head: Rock-Viper 2000/ Range Viper. The belt-cloth from 93 Ninja Scarlett is glued to the back of his head
Arms: Backblast
Chest: Zartan 2000/SA.W.-Viper
Crotch: Effects
Legs: Undertow
Boots: Effects
Gear: Zartan 2000/S.A.W-Viper backpack & rifle, Roadpig armpiece, Backblast knife

Please note that this figure was made long before the Devil's Due comics presented that S.A.W.-Viper as Overkill. But since this figure is one of my favorite customs, I have to show him anyway.

Profile:

The only one of his kind, the Bone-Viper used to be a S.A.W.-Viper that even back then had a reputation for being a maniacal killer. Although not confirmed, he was once the S.A.W.-Viper responsible for the termination of seven G.I.JOE members in Trucial Abysmia during the Cobra invasion of Benzeen. The Joes took a hard revenge on him, one that was meant to kill him. But the S.A.W.-Viper survived the ordeal, for the price of his personal health and pride. With the result of a splintered jaw and knocked-out teeth, he now has a speech impediment. He can no longer pronounce 'R' and he pronounces 'S' as an 'F'. To cover his humiliation, he worked to increase his muscle mass by lifting weights and fashioned himself a new look with the help of a Range-Viper's helmet. He also changed the colors of his uniform to look more menacing. He scarred his left arm with seven marks for his seven kills which he was proud of and wowed that it would become more.

Because of his humiliating defeat, he has become quite obsessed with vengeance, and that has made him even more crazed and bloodthirsty. He has now become a living bone-splinter machine, hence the name 'Bone-Viper'. The other Cobras who didn't like this change nicknamed him 'The Butcher'.

The G.I.JOE team hasn't seen much of the Bone-Viper though. Rumors said that not even Cobra Commander liked him, and had taken necessary measures after a report of an incident on Cobra Island with a renegade Viper whom had shot down Cobra's own troops in an unprovoked action, just because he was bored. The whereabouts of the Bone-Viper today are unknown.