A spider drone appeared close to my city.  I moved my sovereign to attack it, but when it reached the tile where the spider was pictured, nothing happened.  I happened to move the cursor over another tile nearby, and the info card for the spider appeared.  So while it was pictured at the location where my sovereign is (it's hard to see in the screen shot, but there's actually a very small spider at his feet), the spider is actually where I've indicated in the screen shot: