Brain slugs.
At the rate things are currently downhill, 2027 will be the year we welcome our brain slug overlords with open arms and tears of joy because they have finally arrived to relieve us of the burden of cognition, so that we are no longer troubled by how badly we've fucked up as a species.
@cstross Reminds me strongly of the Trills' symbionts in the Star Tek canon. I'd welcome one of *those*!