When the AI is making a sea raid on you and 2 land masses - yours and another (connected or not, but a bay/sea separates them) - are adjacent to their ship, they sometimes land some units on the other. The Japanese loaded a ship to cross the small bay between us (as I had secured the land) and landed one unit on my side of the bay, the rest on theirs (giving them a harder time to round the bay than if they had stayed home). Not that it mattered - I shot the one legion with my musket and used my destroyer for the rest. On their next turn, the Japanese caravel thought maybe it could kill my destroyer (in the red but still fair) and took about one pixel off.