Dream of Piers (also known as Nightmare) is a non-combat pet in Diablo III, added in patch 2.4.2. Players can obtain it by participating in Season Seven and having beaten Chapter 4.
It does not engage monsters, but will pick up any gold it runs over. Visually, it is a recolored version of Unihorn.
The Scribe known as Piers was haunted each night by this being.
Trivia
- The name and description of this pet are a possible reference to the Night Mare by Piers Anthony. This pet is dropped by Ghom