What about Leon Spinks? His career was very up and down with his early career win against Ali in his 8th professional bout to become Heavyweight Champion and pretty much mediocrity after that when he lost the rematch several months later. Almost any fighter of any caliber either won by MD or Stoppage against "Neon Leon".
Good old Leon Spinks had a self-destructive streak that makes the likes of Adrian Broner look like Choir boys.
He went on one big drug and prostitute fuelled party after his win over Ali and stayed partying for the rest of his career.
Trainer George Benton had someone placed outside his door make sure. He did not leave camp for his rematch with Ali. Leon would climb out through the window and be returning from the seedy clubs when everyone was waking up. People was raging at Andy Ruiz jr for not taking his rematch with AJ seriously. Andy is no competition to how Leon trained for his rematch with Ali.
He was once training at the Kronk when he totally disappeared. Manny Steward managed to track him down after a couple of weeks in a seedy motel. High on crack and in bed with Prostitutes.
He went through his money pretty quick. Post retirement suffered continously with Drug and Alchohol addiction problems. Ended up in low paged jobs from working as Mcdonalds to a Janitor.
"Neon" Leon got seduced by the "Neon" lights. He has lived such a roller coaster life that if someone made a movie about him. Nobody would believe it.
There is a movie title in there somewhere from "From Beating Ali to Working at Mcdonalds."