Alice is one of the surviving members of the Saiyan race. She escaped the race's destruction because of her exceptionally violent nature, and because King Vegeta realized she wanted to overthrow him. He exiled her from Planet Vegeta.
Three years after Planet Vegeta was destroyed, Frieza found her and personally recruited her into his ranks.
After distinguishing herself time and again, she rose to a position equal to Ginyu's, becoming an indispensable weapon in Frieza's hands. She was also his most troublesome subordinate...
After all, who else has a subordinate who spends all day plotting to overthrow them and take their place?
So Frieza personally stepped in to give Alice some hands-on personal attention, the physical kind, leaving her flat on her back for several days.
