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Nancy Hofstadter is the late aunt of Leonard Hofstadter.

In "The Zazzy Substitution" episode, Leonard mentions that his Aunt Nancy, like Sheldon, had a multitude of cats. She had dozens while Sheldon had not yet collected his first dozen though he ended up with more than two dozen. When Nancy passed away, the cats turned on her and ate her. Sheldon thinks that was a practical way to go.

Ironically, Nancy is the nickname that Leonard's high school bully, Jimmy Speckerman, gave to him.