I wanted to attack the great oak with my sleet mogi up top. All the other figures shown were in already place. I clicked to attack without realizing it shouldn't be able to, but it flew into the black spot to the left of the grove, attacked from there, then teleported back to its starting place (next to the octopus).

So sleet mogi that is aloft on picture just attacked Great Oak, right?

That's right. The aloft sleet mogi (next to the grove) had just attacked the great oak that round.

Here's a direct link to a larger picture.