B.B. King wasn't the only man to christen a treasured item "Lucille".
"Banks Shot", the twenty-second episode of the first season of The Fresh Prince of Bel-Air, finds lawyer Philip Banks and his butler, Geoffrey, traveling to a pool hall to recover Philip's Mercedes-Benz, which his nephew, Will Smith, has lost to hustlers. Philip gets pressured into playing for stakes; his inept manner ("Geoffrey, get me one of those stick thingies") and losing streak suggest he won't be getting his car back. But when the hustlers agree to raise the stakes to $100 a ball, Philip's demeanor changes immediately: "Geoffrey, break out Lucille." From out Geoffrey's waistband emerges what can only be Phil's cue of choice. Cue montage of Philip hustling the hustlers to the tune of "Soul Man". Unfortunately, the viewer is never given any backstory about Lucille. One could presume that Philip acquired her during his pool hall days that he mentions to Will, but that's as far as one can go.
"Lucille" is also the name of the barbed wire-wrapped, wooden bat wielded by Negan, an antagonist in The Walking Dead. Negan's very crazy about her—he talks about Lucille like she's a living person, and he's almost always shown carrying her; once, when a woman accidentally shot Lucille, Negan had a member of her group executed. Negan wields Lucille against both humans and walkers. In particular, he commits gory, painful, public executions with her, and uses threats of such fates to intimidate others. In the Walking Dead comic series, Negan's late wife is named "Lucille"; presumably this is where the bat got her name. In the TV series, no such backstory is provided.
Interesting similarities, probably coincidental, between guitar-Lucille, cue-Lucille, and bat-Lucille. All three are wooden recreational implements that, by accident or by intention, now have meanings beyond mere entertainment.