The Horklump resembles a fleshy pink mushroom covered in sparse, wiry black bristles. A prodigious breeder, the Horklump can cover an average garden in a matter of days. It spreads sinewy tentacles rather than roots into the ground to search for its preferred food of earthworms.

So why is this classified as a beast? If it resembles a plant, and acts like a plant, why is it classified as a beast?

  • 1
    "acts like a plant"? Most plants don't go hunting for worms – Jenayah Jan 4 at 18:03
  • 1
    The Venemous Tentacula hunts for prey, as do several muggle plants, although they do not move – Ginge Jan 4 at 18:08
  • I'm not sure that the word "beast" necessarily excludes plants anyway, e.g., see this blog post about the Muggle Venus Flytrap. – Harry Johnston Jan 4 at 20:50
  • But it is still classified a plant, is it not? – Ginge Jan 4 at 20:59
  • It might be worth noting that even in the real world mushrooms are Fungi and in a seperate Kingdom of their own compared to Plants and Animals .en.m.wikipedia.org/wiki/Fungus – Sarriesfan Jan 6 at 11:56

Horklumps seem to be very similar to octopi when you look at what's beneath the soil:

Fantastic Beasts and Where to Find Them: Illustrated Edition via the HP Wiki

Thus, I believe that they are considered beasts for the same reason a potted octopus is: its cells do not have rigid cell walls, like plants and fungi do (including the Venus fly trap).


As you see in the description of the Horklump, it is a mobile creature.

The Horklump can cover an average garden in a matter of days.

It is a common mistake that people think it grows to cover the garden, but according to Pottermore, it infests the garden, it does not grow to cover the garden.

Therefore it is a mobile creature. The definition of plant is,

A living organism of the kind exemplified by trees, shrubs, herbs, grasses, ferns, and mosses, typically growing in a permanent site, absorbing water and inorganic substances through its roots, and synthesizing nutrients in its leaves by photosynthesis using the green pigment chlorophyll.

Although this is a "Muggle" definition, it carries over to the wizarding world. The Venomous Tentacula is stationary, and so is the Mandrake. Although they do move, their roots stay in the same place. Therefore, the Horklump is then classified as a beast by it's ability to move to different locations, where other wizarding plants are stationary. Also, as this beast searches for food, it leads us to believe that it does not go through photosynthesis, and that it's main source of food are the worms that it finds.

It spreads it's sinewy tentacles rather than roots into the ground to search for it's favorite food of earthworms.

  • 1
    That means it grows to cover the garden, not that it crosses the garden. It's a common description of plants. – OrangeDog Jan 4 at 18:23
  • The Horklump is a prodigious breeder, and will infest a garden in a matter of days, it can also cover the garden, though. It does not grow to cover the garden. It breeds and moves around so that it's offspring will infest the garden, According to Pottermore – Ginge Jan 4 at 18:28
  • Infest and cover are different things, I see your point, But have you ever seen or heard of a giant mushroom constantly growing to cover an entire garden? – Ginge Jan 4 at 18:29
  • 2
    ... yes, that's what mushrooms and many plants do – OrangeDog Jan 4 at 18:58
  • Are you sure about that? Imagine how hard it would be for Muggles to not see a giant mushroom growing to cover their yard... They cover it on foot, and infest it with their offspring. See the Horklump page on Pottermore and the full description of Horklumps in Fantastic Beasts and Where to Find Them. – Ginge Jan 4 at 19:20

Categorization is hard, even when we're dealing with the Muggle world.

... as just one not-entirely-random example, this very site was originally going be called just "Science Fiction" and then this happened. :-)

(See also How An Algorithm Feels From Inside which tries to explain why we are naturally inclined to believe that "is it a plant or not" should have a single, unambiguous, and clear-cut answer.)

That said, the Horklump does not appear to be very plant-like. Let's go through some typical characteristics that usually distinguish plants from animals, as described, e.g., here, as well as whatever other evidence we have.

  • Description as a "beast". Inconclusive, because even Muggle plants are sometimes described as beasts, but if the same text doesn't describe Venomous Tentacula or Mandrakes as beasts, then this is weak evidence against the Horklump being a plant or fungi.

  • Surface appearance. Described as mushroom-like. Again we immediately run into the problem of categorization being hard, because a biologist will tell you that a mushroom isn't a plant anyway. See also. This is very weak evidence in any case, because ...

  • Overall appearance. Not very plant-like, as shown in Laurel's answer. Suggests that it isn't a plant.

  • Mobility. Plants are usually immobile, animals are usually mobile. Indeterminate. (See the comments under Ginge's answer.) Even if we assume that the Horklump is immobile, however, there are plenty of sessile Muggle animals. We don't know whether the Horklump has any kind of larval stage or not.

  • Cell structure. Indeterminate. This is a work of fantasy, after all. :-) Ditto for respiration and the presence or absence of chlorophyll.

  • Food source. Plants typically make their own food from sunlight. Fungi eat dead plants, more or less. Animals usually eat plants or other animals. The Horklump eats worms, which puts it pretty firmly in the "animal" camp as far as food source goes. (Not conclusive by itself, of course, because of, e.g., Venus Flytraps or Venemous Tentacula.)

  • Sensory and nervous system. Plants typically have "no or very basic ability to sense" whereas animals have a "much more highly developed nervous system". The Horklump's tentacles "search out [...] earthworms", which suggests a functional nervous system. However, the Mandrake is definitely described as a plant, and they have would appear to have disturbingly advanced nervous systems, so I think magic makes this characteristic far less useful than it is in the Muggle world for distinguishing plants and animals.

On the whole, the odds seem to be against the Horklump being a plant or fungi. It seems more likely to be either a sessile animal like a mussel or a slow-moving animal like a slug or snail, depending on how you interpret the text. But in the absence of information on the cellular structure, detailed behavioural characteristics, and life-cycle, not to mention the phylogenetic history, this really can only be a best guess.

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