In the upper left, an open-mouthed black horse stands next to some red curtains, though the unconscious blond woman sprawled upon the bed doesn't notice it, anymore than she notices the troll-like figure seated on her chest.  
This work was created in the aftermath of the artist's failed affair with Anna Landolt, the niece of Johann Casper Lavater.  It was the inspiration of Charles Nodier's story Smarra, while it became more popular in England after a version of it appeared in The Botanical Garden.  In the same year it was painted, its artist created The Oath of the Ruttli.  In the painting, a small wooden table on the lower left supports several vials.  In the upper left, an open-mouthed black horse stands next to some red curtains, though the unconscious blond woman sprawled upon the bed doesn't notice it, anymore than she notices the troll-like figure seated on her chest.  FTP, name this 1781 painting by Henry Fuseli.
This work was created in the aftermath of the artist's failed affair with Anna Landolt, the niece of Johann Casper Lavater.  
The Nightmare