Source: Horror Adventures, pg(s). 242
Trompe l'oeils are magical, masterpiece life-sized portraits capable of stepping out of their canvases. They closely resemble their original models, but can be revealed as being made of paint on close examination. Trompe l'oeils can either be created intentionally or spontaneously arise from an extremely lifelike painting; in the latter case, the trompe l'oeil will believe itself better than the original and seek to replace it.
A trompe l'oeil is connected to the surface on which it was painted. If destroyed, it will automatically reform from the portrait unless the canvas (or the painting, if it was painted on a wall) is destroyed as well.