The painting "The Ambassadors" by Hans Holbein the Younger includes a distorted image of what object?

In Hans Holbein the Younger's painting "The Ambassadors," the distorted image of the skull serves as an important memento mori, a symbolic reminder of mortality and the transient nature of life. Positioned at the bottom of the composition, the skull is painted in such a way that it appears as a trompe-l'oeil (a trick of the eye) illusion, only becoming recognizable when viewed from a specific angle. This element emphasizes the theme of knowledge and the inevitable fate that awaits all humans, juxtaposing the displays of wealth and worldly achievements represented by the other objects in the painting. Holbein's use of a skull, particularly in the context of a portrait celebrating the intellectual and social stature of the two men depicted, serves to remind viewers of the vanity of earthly pursuits and the significance of life beyond material possessions.