Floyd Mayweather channeled his inner-Bob Barker for his son's 16th birthday party ... 'cause he gave away A BRAND NEW CAR!!!!!
The guest of honor was Zion Mayweather -- who was celebrated with a live performance from Young Thug while go-go dancers busted out bottle service (non-alcoholic, we think)!!
There was 360 degree photo booth, pool tables and one of those "money machines" -- where you stand in the glass case and collect all the bills you can grab in 30 seconds while a fan blows the cash around.
Oh, and Zion also got a brand new Mercedes-Benz ... so, yeah ... he's happy!