If you immediately thought "leeroy jenkins" you're actually not far away from the heart of it.
Florence Foster Jenkins(born
Narcissa
Florence Foster;[a] July 19, 1868 November 26, 1944) was an American socialite and amateur coloratura soprano who became known, and mocked, for her flamboyant performance costumes and notably poor singing ability. Stephen Pile ranked her "the world's worst opera singer ... No one, before or since, has succeeded in liberating themselves quite so completely from the shackles of musical notation."[1]
Florence liked to pick virtuosic pieces to sing despite having no skill or talent. She supplemented her lack of ability by having an absurd amount of familial wealth. She'd host private parties and shows and carefully control the guest list. She was aware she had detractors but it's a little unclear if she was aware she was terrible.
An actual clip of her trying to sing:
https://en.wikipedia.org/wiki/File:Florence_Foster_Jenkins_H%C3%B6lle_Rache.ogg
It's insane that she tried to do this piece. I mean that's like a person who can't do a handstand trying to do a quadruple somersault into a pool.
She developed a cult following of celebrities, music lovers and critics.
Unironically inspiring quote: "People may say I can't sing," she once remarked to a friend, "but no one can ever say I didn't sing."