How to block a someone from commenting?

I keep getting spammed by the same user, well different name and site listed but always the same email, IP, and comment.

the email is 1p@ultradrugbuy.com, the IP is 31.184.238.9, and the message is long and always the same.

I want to do 2 things:

• How can I block this person from commenting?
• I have over a hundred pending from them, is there a way to mark them all as
  spam?

In Settings > Discussion > Comment Blacklist. You can blacklist comments based on content, name, url, e-mail, or IP.

To mark the comments as spam, what I would do, is to do a search for his IP and then there is a checkbox that will select all, then just mark as spam. Trick is, it only applies to the comments listed on the page, but it is still better to do a few and a lot.