Johnny Flynn is an antagonistic character mentioned in the famous nursery rhyme, Ding Dong Bell - he is a young boy who threw a cat into a well to try and drown it, his actions being foiled by another boy.

In fact the entire nursery rhyme exists to tell of Johnny's crime and scold the boy.

The Rhyme

Ding, dong, bell,
Pussy’s in the well.
Who put her in?
Little Johnny Flynn.
Who pulled her out?
Little Tommy Stout.
What a naughty boy was that,
To try to drown poor pussy cat,
Who ne’er did him any harm,
But killed all the mice in the farmer's barn