Located on the cliff overlooking the burned cabin. Go through the tunnel that leads from the cabin toward the witch's tower. Pass all the spiders, up the stairs. At the top of the stairwell exit, turn right and go along the edge of the top of the hallway. The cliff is a short walk back, and skriekscon is in the far corner.
A giant bat.
Note that the image with all the Crow's Wood champions locations has the wrong location for where Shriekscorn spawns.