Eldritch Abomination: There have been a few elder races and Gone Horribly Right seed AI, and other postsophont entities, that are not terribly, shall we say, sophont-friendly, or indeed sophont-comprehensible.  (Start with the Leviathan Consciousness, and work down the list.)  And statistics – and bright EM spots elsewhere in the galaxy – suggest that there are probably more than a few more of those out there.

Do not ask.  You might find out.