How can we stop this spamming madness?

Recently I’ve noticed a new kind of spammers. They spam by answering questions, many of which date back to around 2008. The answers are always in Chinese or Japanese. And they spam with the speed of 5 responses per second! (My main frustration)

I’ve seen two of this kind and I am unable to flag all of their spams since they spam so fast. Right now a spammer like that is roaming, and I get too exhausted chasing and flagging them.

Is that a bot? How can a human spam that fast? Is there any way we can stop this kind of spam?

Sorry for the venting :p