So not a 500mm f8 lens then.
Is it Canon EF-M 28mm f3.5 macro ?
Give us at least a little hint... which mount for instance?
Could it be the Laowa 9mm f2.8 for Fuji? ;-)
That one was long since announced, yes.
While there hasn't been anything to read, I've compiled the list of still unreviewed lenses out of boredom. It's... scary.
P. S. Is Markus all right?