Hey diddle diddle,
I’ll ask you a riddle.
What element is named for the moon?
It’s in photocells,
And is useful as well,
When you want itchy dandruff cured soon.

Hey diddle diddle,
I’ll answer your riddle,
Selenium’s named for the moon.
But whatever you do,
Avoid SeH2
It smells so bad you’re likely to swoon.

Based on Hey Diddle Diddle
Learn more about Selenium