That kind of activity does indeed deserve close scrutiny. I wouldn’t just let it ride without first taking a closer look at the activity.
If the traffic volume is normal and the CTR jumps that high, then it could be a particularly appealing ad, but if you had a spike in traffic, take a closer look at the locations the traffic is coming from.
Is it from the usual geographic region you normally see for this site? Are most of the clicks coming from a small set of IP addresses, or from unusual geographic locations? If so, start blocking those locations.
If you are convinced that you are being click-bombed, go ahead and disable ads for a period of time to see if the traffic goes away. When it does, re-enable your ads.