I'm trying to emulate the behavior of the heron in the island demo. That prefab has underneath it an animation node, HeronAnimated, which in turn has a list of animation clips. This note has an icon identical to the prefab one, but one level below in the hierarchy.

When I create an empty prefab and then try to drag animation clips into it, only the first works. The second time I try to drag in a clip, I get a warning dialog about a "possible unwanted prefab replacement" Also, I cannot seem to create a new "animation" (Assets->Create->Animation interface actually creates an animation clip at top level, not an animation node under the prefab).

I can manually add animation clips to the prefab animation object in the inspector by upping the size count and then pointing to other animation clips.

However, when I try from script to reference any of the animations, I get a null reference exception.

I am new to Unity. I have tried both the character and scripting tutorials to no avail...