I heard this gruesome rhyme on the radio last night. I vaguely remember it from childhood, although I was, and am, a nail-biter rather than a thumb-sucker

“The great tall tailor always comes To little boys that suck their thumbs, And ere they dream what he’s about. He takes his great sharp scissors out And cuts their thumbs clean off, -and then, You know, they never grow again.”

It’s from a longer poem by Heinrich Hoffman - The Story of Little Suck-a-thumb