Floyd Mayweather pulled off the ultimate feint ... the boxing legend took friend, businessman Robert Smith to look at property -- at least, that's where the billionaire investor thought they were going -- but in reality, the 50-0 legend delivered Smith to his surprise 60th birthday party!
"When Robert walked into his house he was shocked to see us all there. He was really surprised and had no clue that his family threw him a surprise party," Mayweather tells TMZ Sports.
And, the Palm Beach, FL party was awesome .