Last week, a woman named Therra Gwyn Jaramillo described, over the course of more than 1,200 words on Facebook, how a man named Chris had bought her groceries at Whole Foods — $375 worth — in a moment of grave need. (She was strapped, and a friend had sent her to the expensive store with a $250 gift card.)

She had not recognized her benefactor at first. But soon, the cashier told her that the Chris who bought her groceries was, in fact, Ludacris, the artist behind such hits as “What’s Your Fantasy?”, “Southern Hospitality,” “Saturday (Oooh! Ooooh!)” and “Stand Up.”

Upon learning who had bought her groceries, Ms. Jaramillo burst into what she described as “the worst possible white-woman rendition” of Ludacris’s song “Rollout (My Business).”

“Ludacris,” she wrote. “This guy is awesome run amok. You know why? He was just doing something kind for a disheveled, harried stranger.”