Hearth is an ever-changing sentient dungeon, created by a wizard to hide away treasures. However, the wizard forgot to make Hearth evil, so, instead of crushing adventurers they tend to befriend them and give them snacks instead.

The little dragon knocker is animated and can move around the door, and hold the ring in its front legs or tail.

The mail slot leads to a little pocket dimension where the dragon stores things like spell components.

One of Hearth's limitations is that they cannot open the door by themself, someone has to open the door by themself to go inside. Hearth can, however, as a person skilled in conjuration magic, teleport their entrance to a different location.

Inside the door, Hearth has control over the environment. They like to manifest a sitting room with comfy chairs surrounding a fireplace. Nothing about them appears to change when looked at, but when people look away and back, they may find that the rooms and furnishings have shifted.

The dragon can't leave the door to travel the outside world, but it can enter the rooms inside and move around there. Hearth tends not to do this though, since that leaves them blind to the outside world.

INTERACTION ART IS MUCH LOVED AND APPRECIATED!