Slitherine

In a multiplayer game, while mistakenly thinking the turn had started (during alien movement, I wasn't host) I was editing a build queue and ended up with duplicates (save attached). After letting the first one build, the second one started, and after a while, changed into a headquarters.

I was the terra, it was my smallest city on the right >< I had just built it the previously. Edit: Suess.