Robert Ernie "Babo"[1] Castillo Jr. (April 18, 1955 – June 30, 2014) was an American professional baseball pitcher.

He played for the Los Angeles Dodgers and Minnesota Twins of Major League Baseball (MLB) between 1977 and 1985.

He was in the bullpen for the Dodgers in the 1981 World Series, pitching one inning against the New York Yankees.

Castillo is credited with teaching his former Dodgers teammate, Fernando Valenzuela, how to throw a screwball.

[2][3] Castillo died on June 30, 2014, from cancer at the age of 59.