Hidebehind

The Hidebehind is a tall, nocturnal, and highly dangerous magical beast native to the forests of North America. Known for its remarkable ability to conceal itself behind almost any object, it is a stealthy predator of humans. The creature is historically significant as its silvery hair was one of the first types of wand core material used in wands crafted at Ilvermorny School of Witchcraft and Wizardry (Pottermore).

A Hidebehind is described as a tall, powerful creature that, when standing, bears a resemblance to a “skinny, silver-haired bear” (Pottermore). Its most defining characteristic is its ability to contort its body to hide perfectly behind nearly any form of cover, from trees to drainpipes, making it exceptionally difficult to locate. It is a nocturnal hunter and is known to prey specifically on humans, disembowelling its victims. The only known creature capable of detecting and repelling a Hidebehind is the Pukwudgie (Pottermore).

• Stealth and Concealment: The Hidebehind's primary magical ability is its power of concealment. It can physically compress and contort itself to fit behind any solid object, rendering it effectively invisible to its prey until it chooses to strike (Pottermore).
• Strength and Ferocity: As a predator capable of overpowering and disembowelling human victims, the Hidebehind possesses considerable physical strength and aggression (Pottermore).

The Hidebehind is indigenous to the forests of Massachusetts in North America (Pottermore). The most famous account of a Hidebehind involves the founders of Ilvermorny. While living in a small cottage on Mount Greylock, Isolt Sayre and James Steward's adopted sons, Chadwick Boot and Webster Boot, ventured into the woods and were attacked by a Hidebehind that had been preying on local No-Majs (Pottermore). The boys were saved by a Pukwudgie named William, who had befriended Isolt Sayre. William managed to kill the Hidebehind with a poison-tipped arrow. Upon examining the creature's body, Isolt and James discovered that its long, silky, silver hair possessed magical properties suitable for use as a wand core. They incorporated the hair into the first wands they created for Chadwick and Webster, marking the beginning of Ilvermorny's unique wandmaking tradition (Pottermore).

The name “Hidebehind” is a literal English compound word, formed from “hide” and “behind.” This name directly describes the creature's signature behaviour of hiding behind objects to stalk its prey.

• The Hidebehind does not appear in the original seven Harry Potter novels. Its existence and lore were created by J.K. Rowling for the Pottermore website as part of the “Magic in North America” collection, which provides backstory for Ilvermorny school and the North American magical community.
• According to supplementary material for the film Fantastic Beasts and Where to Find Them, wands containing a Hidebehind hair core are sensitive and highly attuned to their owner's emotions. They are also capable of performing powerful and subtle magic, but their owners may not necessarily be drawn to the Dark Arts (Fantastic Beasts and Where to Find Them).