Parks was not supposed to be in Vol. 2 at all. The Mexican pimp, Esteban Vihaio, was originally given to Ricardo Montalban. However, when Montalban missed a script reading, Parks happened to be on hand and Tarantino asked him to fill in and read the part. He was so good that QT decided then and there that he should play the part in the film, prompting David Carridine to later remark that he would never, ever miss one of Quentin's readings.
Here is Michael Parks as Esteban Vihaio, the last stop for The Bride on her way to the titular killing of Bill. I also really dig the music here, as it perfectly sets up this great moment.