Fantastic Beasts explains how Hagrid (Robbie Coltrane) got Aragog while he was a student at Hogwarts. The Fantastic Beasts saga follows Newt Scamander (Eddie Redmayne) traveling the world in pursuit of magical creatures - after having been commissioned to write a book on them - in the 1920s. While Fantastic Beasts 2 shifted the focus from Newt to Dumbledore's (Jude Law) war against his friend-turned-foe Gellert Grindelwald (Johnny Depp/Mads Mikkelsen), Newt and his fantastic beasts remained a key theme, as Newt reminds his friends, "There are no strange creatures, only blinkered people."
Much like Newt, Hagrid has had a lifelong passion for magical creatures, making it his goal to help people see even the most ferocious beasts as "seriously misunderstood creatures." This echoes Newt's statement to Tina Goldstein (Katherine Waterston), who thought Newt was writing Fantastic Beasts and Where to Find Them as an extermination guide: "to help people understand why we should be protecting these creatures instead of killing them." Hagrid's love for Acromantulas eventually resulted in his expulsion from Hogwarts, as Tom Riddle (Christian Coulson) caught Hagrid caring for Aragog and framed him for Myrtle's death. But J.K. Rowling hasn't yet revealed the exact details of how Hagrid got Aragog.
In Harry Potter and the Chamber of Secrets, Aragog tells Harry (Daniel Radcliffe) he came to Hogwarts from a distant land, “in the pocket of a traveler.” Newt is famous for keeping magical creatures in his pockets, his bowtruckle Pickett being a trusty sidekick by Fantastic Beasts 3. Moreover, Newt did travel the world before returning to the UK and continuing his achievements in Magizoology: "I have visited lairs, burrows, and nests across five continents, observed the curious habits of magical beasts in a hundred countries, witnessed their powers, gained their trust and, on occasion, beaten them off with my traveling kettle." It would thus come as no surprise if Newt was the one to give Aragog to young Hagrid in the 1940s.
Very similarly to Hagrid, Newt was wrongly expelled from Hogwarts following an event with magical creatures. Except in Newt's case, he was covering for Leta Lestrange's (Zoë Kravitz) experiment with a Jarvey. Understanding Newt's kind nature, Dumbledore argued strongly on Newt's behalf and managed to help him retain his wand outside of Hogwarts. But neither Newt nor Hagrid lose their love for magical creatures after their unfortunate expulsions - if anything, their love only grows stronger. Hagrid receives Aragog as a young student, and the "traveler" is most likely a person who sees Hagrid as someone who understands all fantastic beasts - and no one fits this description better than Newt himself.
Hagrid received Aragog sometime before 1943 (when Tom Riddle orchestrated his expulsion), meaning this moment might fit into the fifth Fantastic Beasts movie, as the five-movie series will explore the years between 1926 - 1945, ending with the defeat of Grindelwald. In 1979, Newt was awarded the Order of Merlin, Second Class, for his services to Magizoology, and even had a Chocolate Frog Card named after him - as well as a real world PETA article praising him as a "Magical Animal Ally." It's only fitting that Fantastic Beasts connects its fiercest animal rights activist to his counterpart in the Harry Potter series, fan-favorite Rubeus Hagrid, through Aragog.
Next: Fantastic Beasts 3 Theory: Dumbledore's Mother Is Secretly Alive
