I don't think Floyd is the only one to have done it, but he did it best and I bring him up because his supporters never want to admit that he played that game even though he basically bragged about it.
I wish I could find it, but there was an interview with him and he was asked about whether he thought he was really better than Sugar Ray Leonard. Floyd said yes because he was undefeated. The interviewer pointed out that Sugar Ray had several fights against tough competitors while those competitors were in their prime, and Floyd's response was basically that it was Sugar Ray's fault for taking those fights when he did.