Horned Slugs

• Type: Magical Creature, Potion Ingredient
• Key Features: Having one or more horns
• Value: A valuable potion ingredient, though considered less rare than Unicorn hair or Acromantula venom.

Horned Slugs are a type of magical creature used in potion-making. While no detailed physical description exists in the novels, their name strongly implies they are a variant of common slugs, distinguished by the presence of horns. Their primary significance in the wizarding world is as a potion ingredient. The task of preparing them for potions, such as chopping them, is shown to be a tedious and unpleasant chore, suitable for a school detention. Professor Slughorn considered them a valuable ingredient, though he ultimately deemed them less valuable than a pint of Acromantula venom. It is also theoretically possible for a human to be transfigured into a Horned Slug, as this was a question on the Transfiguration O.W.L. exam.

• Harry Potter and the Chamber of Secrets: After Neville Longbottom melts Seamus Finnigan's cauldron during a Potions lesson, Professor Snape assigns him a detention chopping up barrels of Horned Slugs.
• Harry Potter and the Order of the Phoenix: On their Transfiguration theory O.W.L. exam, Harry Potter and his classmates are asked to “Describe the circumstances under which a human being might be transfigured into a horned slug.”
• Harry Potter and the Half-Blood Prince: While collecting valuable venom from the corpse of the Acromantula Aragog, Horace Slughorn muses on what ingredient might be a worthy trade for it. He briefly considers Horned Slugs before dismissing them in favor of something rarer like Unicorn hair, establishing their place in the hierarchy of valuable ingredients.

• In the Harry Potter and the Chamber of Secrets video game, Horned Slug Mucus is an ingredient for the Swelling Solution. (video game)
• In the Hogwarts Legacy video game, Horned Slugs can be found in various caves and their horns are a necessary ingredient for brewing the Wiggenweld Potion. (video game)