Nolzur's Marvelous Pigments

From Dungeon Master's Guide, page 183. Found on Magic Item Table D.

Description
Wondrous item, very rare.

Typically found in 1d4 pots inside a fine wooden box with a brush (weighing 1 pound in total), these pigments allow you to create three-dimensional objects by painting them in two dimensions. The paint flows from the brush to form the desired object as you concentrate on its image.

Each pot of paint is sufficient to cover 1,000 square feet of a surface, which lets you create inanimate objects or terrain features — such as a door, a pit, flowers, trees, cells, rooms, or weapons — that are up to 10,000 cubic feet. It takes 10 minutes to cover 100 square feet.

When you complete the painting, the object or terrain feature depicted becomes a real, nonmagical object. Thus, painting a door on a wall creates an actual door that can be opened to whatever is beyond. Painting a pit on a floor creates a real pit, and its depth counts against the total area of objects you create.

Nothing created by the pigments can have a value greater than 25 gp. If you paint an object of greater value (such as a diamond or a pile of gold), the object looks authentic, but close inspection reveals it is made from paste, bone, or some other worthless material.

If you paint a form of energy such as fire or lightning, the energy appears but dissipates as soon as you complete the painting, doing no harm to anything.