I assume that some site has hostgator-related links with two slashes instead of one. Due to the two slashes, the GoogleBot doesn't realize that it's indexing their own results pages.

They disallow /search

    User-agent: *
    Disallow: /search

but maybe //search slipped thorough?

This is just a bug, sorry.

They probably want to index some pages on google.com, but not search results. To exclude search results, someone wrote something to exclude URLs that start with /search, and forgot that //search works the same way.