Streeler Shells

• Type: Potion Ingredient
• Owners: Harvested from Streelers; sold in apothecaries.
• Maker: Sourced from the magical creature, the Streeler.

Streeler Shells are the protective outer coverings of Streelers, a species of giant magical snail. The most remarkable feature of these shells is their ability to change color in a vibrant, kaleidoscopic display, a trait they share with the creature itself, which is known to change its hue every hour. The shells are often described as being covered in sharp spines, which can make handling and processing them for potion-making a difficult task (Pottermore). Their size corresponds to that of the giant snail they come from.

The primary and most well-known use for Streeler Shells is as a potion ingredient. Although their specific properties are not detailed in the Hogwarts curriculum covered in the novels, they are widely used in the broader world of Potioneering.

• Thickening Agent: Streeler Shells are known to be a key thickening agent in various concoctions (Pottermore).
• Color-Changing Properties: It is believed that the shells may impart their color-changing characteristics to the potions they are used in.

It is important to distinguish the shell from the creature's venom. The venomous slime trail left by a Streeler is highly toxic and is one of the few known substances that can kill Horklumps. The shell itself is not noted to possess this venomous property.

Streelers are native to several African countries but have been bred by wizards across Europe, Asia, and the Americas due to the demand for their shells and the fascination with their color-changing nature. The ownership of a live Streeler requires a license from the Ministry of Magic, suggesting that the trade of their parts, including the shells, is likely regulated. As a result, Streeler Shells have become a standard, if somewhat exotic, ingredient found in wizarding apothecaries, such as the shop on Diagon Alley, available for purchase by students and accomplished potioneers alike.

While not specifically mentioned within the narrative of the seven original novels, Streeler Shells are an established part of the wizarding world's magical inventory. Their existence is confirmed through the Hogwarts textbook, Fantastic Beasts and Where to Find Them, which describes the Streeler creature in detail. This textbook is a required reading for first-year students, placing the creature and its by-products firmly within the canonical universe known to the characters.

• The primary source of canonical information on the Streeler and its shell comes from the Fantastic Beasts and Where to Find Them textbook, written by J.K. Rowling.
• In the video game adaptation of Harry Potter and the Philosopher's Stone, Streeler Shells are a common potion ingredient that Harry Potter must collect for Severus Snape's lessons.
• Information on the Pottermore (now Wizarding World) website further elaborates on the shells' use as a thickening agent and their spiny physical nature (Pottermore).