I’m just a hobbyist so I thought that this might get me off my behind and do something. 
My door will be a D&D dungeon door in a ruined tower. A wizard had placed a protection spell on the door (and tower) to keep them safe. Centuries later the spell has weakened and the door and tower have started to crumble. This has let other creatures get access through the door.
I have attached some concept sketches which might change as I do this. I have never done this so I’m sure I will mess something up somewhere. 