Ask HN: Have you ever been targeted by a negative SEO attack?

We run a small open-source project (Intlayer) and recently saw a 10x traffic spike from suspicious IPs, mimicking Googlebot and hitting random pages every few seconds.

It looked like someone was trying to get us penalized by Google. We wrote a post explaining what happened and how we responded.

Curious if others have seen something similar and what tools or strategies you use to detect/prevent this?