Why do you think it hasn't been more successful?

[Bad News Gertner]

Originally Posted by Lock Jaw Yeah, there was a reason why GI Joe wanted him. Fun Fact: After seeing the success/renewed interest that Sgt Slaughter brought to GI Joe, they started to think about what other "outside character" they could bring in. A deal was struck to bring Rocky Balboa into the GI Joe universe. He was listed as a member in one issue of Marvel's GI Joe comic book with a bio and some art of him. The deal fell through, and the very next month Marvel printed a retraction saying "Rocky Balboa was incorrectly listed as a member of the GI Joe. He has never been a member or affiliated in any way."

Slaughter first appeared in 85, which was after his second WWF run had already ended. I heard that about Rocky. Pretty crazy