Which Cubs legend was nicknamed "Mr. Cub"?

Which player was nicknamed "The Kid" and had one of baseball's most admired swings? Which pitcher was nicknamed "The Big Unit"? Which pitcher was nicknamed "The Rocket"? Which Red Sox slugger was nicknamed "Big Papi"? Which Padres star was nicknamed "Mr. Padre"? Which Cardinals shortstop was nicknamed "The Wizard" for his fielding? Which White Sox slugger was nicknamed "The Big Hurt"? Which Yankees closer entered games to "Enter Sandman"?