Thats the original map, If you go to where the red is on the bottom side or the wall of dragon pit on that side, you see just some trees up there, Now when you go into a game look at the same spot, There is a rock that looks like a head
I am not sure if this is what you're talking about but there is a dragon's carving near the entrance to the river in-between dragon and the middle lane?
Also I don't think this is a teaser, that's probably just a landmark for "dragon lair: Beware" there is also quite a few change between the linked map and the current one. There is something akin to a cave on the isolated wall of tri-brush (blue side) and some kind of altar near blue of the red side facing toward the river. Just to list a few.
