Naked Googlebot?

I am stumped with this Google IP hit

[not2easy]

just one hit from:

66.249.80.50 - - [25/May/2014:21:34:17 -0500] "GET /large-original.jpg HTTP/1.1" 200 70037 "http://spamsite-referer dot net/" "Mozilla/5.0 (iPhone; CPU iPhone OS 7_1_1 like Mac OS X) AppleWebKit/537.51.1 (KHTML, like Gecko) CriOS/34.0.1847.18 Mobile/11D201 Safari/9537.53"

I did visit the site via a search and found no link there to this image from the "referring" URL. I have been planning to move and rename that particular image because it was added for an announcement about 8 months ago that is no longer on this site. My question: it looks like nothing more than common referer spam, but I am curious about the IP and UA combination. It makes no sense.

[thetrasher]

Hostname is google-proxy-66-249-80-50.google.com

[not2easy]

Thanks thetrasher, that helps. It doesn't show that in my data but it makes more sense.
My Mac Utilities Network Tools only shows Google. period. I do see the rest of the info with an online lookup. Something I'll keep in mind.

[dupres01]

should 66.249.80.50 be blocked? i guess i need to learn about google proxys.

[lucy24]

You could make a pair of rules:
(a) block anything from 66.249.whatever-it-is* that doesn't identify itself as Googlebot
and (you've probably got this second one already)
(b) block anything that calls itself Googleboat [NC] that isn't from 66.249.whatever


* I've got it written down but never internalized it. I know that domaintools is elsewhere in 66.249, which always throws me.