My used-to-be-friend-now-good-for-nothing-bully Relias decided he'd rather capture my cities than admire them from afar, and brought along a catapult. I engaged said catapult (along with its escorting swordsman and archer units) before it got to my city. In the battle it did manage to get off a shot at my grouped archers in the back (youch!) and in doing so its graphic rolled all the way up to them, then did an animation, did splash damage, and disappeared. I had to mouse over every tile on the map to figure out where it was.

Also, I had no idea what a catapult did as the informational text about it didn't say anything about any kind of attack, let alone splash damage. I think it deserves another looking-at.