So firstname.lastname@example.org got the following reply:
Kindly go fuck yourself. Preferably with a dildo covered in barbed wire. Repeatedly.
It's rare that I swear, but I'll make an exception in their case. And cut-n-paste it into a few of the many others in the inbox.
They also operate under the name ethical-seo-comapany.com (no, the typo is not mine - they actually don't know how to spell company).
Just make sure you check the headers before doing anything similar to make sure the spammer isn't really someone pulling a joe job.
The rest of them got this enhanced versin:
Kindly go fuck yourself. Preferably with an aids-infected dildo covered in barbed wire. Repeat until you remove yourself from the gene pool.