What would you do if you won $1 million? Well, Kayla Harrison's got the money ... and some ideas on how to spend it.
Harrison -- one of the biggest stars in MMA -- beat Larissa Pacheco and won this year's PFL tournament ... which comes with an over-sized million dollar check.
So, we hit her up and asked how she's gonna spend the money ... and she's considering using part of the big ass check to honor her father.
"My dad passed away a while ago and he used to love fixing up old American muscle cars.