Here is an example:
> skyrim english voice files (and subtitles) latest version
You get no results with my search engine, but interestingly, if you feed that into google, you get some pretty dodgy top results.
It looks like the type of SEO spam nonsense you find on websites, hacked wordpress deployments are often rife with these types of keywords. I think they are trying to manipulate a would-be suggestion algorithm somehow. Problem is I don't do anything with the user input.
There also seems to be a few distinct bots doing this, with distinct user agents (but bots with the same UA spam-search on the same topic out of epharma, casino, warez).
I also have another, identical search box in another part of the site and it has never seen any sort of spam bots.
Nobody seems to write much about it, maybe because they don't want to give people ideas, but it's an endlessly fascinating subject.
But also, interesting.