He is staggeringly difficult to hurt, that much is pretty obvious. Some guys appear to coast to victory and actually take more punishment than Floyd has in almost all of his "tough" fights.

He did touch down against Judah for sure, can't remember the Hernandez one. Shane Mosley and Corley were able to legitimately rock him, and Castillo deserved the win in their first fight, being the only person with that argument imo.