To OP,
Just hit the report to moderator button and leave a comment in the report comment box. It will be dealt. There are bots all around the forum. We have seen them in the past and we will see them in the future too.
Thanks for the info, I knew it.
I created a thread to stop this particular bot, because it uses the same text from different accounts everywhere, which allows it to continue sending spam even if the account is blocked.