Question Non-humanoid avatar

Hello!
I'm working with 2D animation.
To add the mask to an Animation Layer, I created Avatar mask. But under section Transform it needs Avatar. I have a 2D Sprite, a dragon. I can't use humanoid Avatar.
I don't know how to create Avatar for non-humanoid animation!

I've read this articles multiple times:
https://docs.unity3d.com/2017.1/Documentation/Manual/class-Avatar.html
https://docs.unity3d.com/Manual/GenericAnimations.html
https://docs.unity3d.com/Manual/class-AvatarMask.html#Transform

I'm not using any 3D model importing, so I don't have any Rig section. I couldn't find any "Avatar" menu in "Create"/"Component" (if such exists). The only thing I could find is "Build Generic Avatar" in Animator menu, but I can't save it anywhere to put in Transform section of Avatar mask.

 

No one uses non-humanoid avatars or forum is dead?

 

Unity: Is there a 2D equivalent to the avatar mask that is used on the animator layers? stackoverflow.com