Forbidden Forest Acromantula colony

A colony of Acromantulas was established in the Forbidden Forest at Hogwarts School of Witchcraft and Wizardry in 1942.

Establishment of the colony
The colony was established in 1942, when a young Rubeus Hagrid, a third year student at Hogwarts School of Witchcraft and Wizardry, acquired the egg of an Acromantula from a traveller. He raised the creature in secret, naming it Aragog, feeding it on leftovers. However, during the same year, Tom Marvolo Riddle learned how to open the Chamber of Secrets, and released the Basilisk. Riddle, finding out about Hagrid and the Acromantula, diverted attention away from himself by blaming the attacks on the spider. Hagrid was expelled, but he managed to release Aragog into the Forbidden Forest.

Dealings with Hagrid
Aragog survived in the Forbidden Forest, and Hagrid helped him as much as possible. He acquired another Acromantula, a female named Mosag, as a mate for Aragog and the two Acromantulas bred. The growing number of spiders built a huge dome web in the forest. Hagrid occassionally visited them, and Aragog, grateful for Hagrid's assistance, commanded his children not to attack and eat him.

Harry Potter and the reopening of the Chamber of Secrets
In 1993, Harry Potter was directed to the Acromantula colony by Hagrid to learn about what had transpired fifty years previously. The Chamber of Secrets had been reopened, and Hagrid was unable to tell them of the events leading up to his expulsion since he was placed under arrest and sent to Azkaban as a prime suspect. Hagrid told Harry and Ron Weasley to "follow the spiders". The pair did, and Aragog relayed the tale of his birth and what transpired in 1942. However, his orders to his children not to attack Hagrid did not extend to Hagrid's friends. He allowed his children to attack the pair, but the two students were saved by a feral flying car.

Death of Aragog
In 1997, Aragog sickened and died. The colony, as was their way, intended to devour the corpse. Hagrid, wanting to give him a decent burial, dragged the corpse through the Forest and buried it outside his hut in a small service attended by Professor Horace Slughorn (who used the opportunity to procure some Acromantula venom), and Harry Potter.

The Battle of Hogwarts
During the Battle of Hogwarts in 1998, the Acromantulas were driven out of their nest by Death Eaters, who used the nest as a base of operations. The Acromantulas attacked the school, scaling the walls of the castle and attacking both the defenders of Hogwarts and Death Eaters alike.

Near the climax of the battle, the nest was the location of Harry Potter's stand against Lord Voldemort, when he fully intended to sacrifice himself in order to defeat the Dark Lord.

Appearances

 * Harry Potter and the Chamber of Secrets
 * Harry Potter and the Chamber of Secrets (film)
 * Harry Potter and the Half-Blood Prince
 * Harry Potter and the Deathly Hallows