Lyrics:

The amoeba is so small you need a microscope to see one
It hurts the eyes, but I'll concede I'd rather see then be one

They never sing or laugh or talk or eat fondue or quiche
And if you take one for a walk, you need a tiny leash

I know the thing must have a brain, although I couldn't tell you where
It sure must be an awful pain to be so unicellular