Flibbety-flam-bams
 
Flibbety-flam-bams are a very strange lot;
They only have properties others aint got.
They do not have mass, nor height, width or length;
No center of gravity, and no tensile strength.
No location for them, no velocity too;
No properties in common with me or with you.
You never will see one, you'll never detect one
Cause photons pass thru them, they cannot reflect one.