Google DoS
I've been on the receiving end of a Google DoS and there is literally nothing you can do about it.
Our internet connection at work suddenly stopped responding. The modem showed activity, but requests going out timed out. I pulled up the firewall and monitored it, a single IP address was bombarding our internet connection with traffic. We had a 10 mbps connection at the time and it was saturated. I recorded the IP address and did a look-up (over mobile data), it was registered as an address in one of Google's California datacentres.
I tried calling them, no way to get through to a human and just constantly telling me to use the relevant part of the Google website... Only, there was nothing on the Google website about what to do, if Google is DoSing you! So I tried their mail addresses for abuse and webmaster, both returned automated replies informing me that the emails had been automatically deleted without reading. Even pinging them on Twitter didn't do anything. In the end, I contacted our ISP and they weren't happy either, our 10mbps conection was being flooded, but the server was pushing well over 1gbps into their network! They put a perimeter IP block on the address. The first month was free, after that, we would have to pay.
Luckily, we were in the middle of switching providers, so we quickly moved over to the new provider and new IP address. After the month ran out, we didn't extend the IP block. The contract with the old provider ran another 3 months. I checked in, just before the contract was due to end, that Google server was still pumping the gpbs to our address (well, I assume it was still pumping 1gbps, but more than the 10mpbs that the line was capable of).