The character of Hagrid was based on a real biker
In Harry Potter: Page to Screen: The Complete Filmmaking Journey, according to Robbie Coltrane, who played Hagrid in the Harry Potter films, the character was modelled on a real biker. Coltrane said that J.K. Rowling told him that Hagrid was ‘based on a Hell's Angel she knew in the West Country’. ‘He was just huge and terrifying,’ Coltrane recalled Rowling telling him. ‘And then he would sit down and talk about his garden and how his petunias had been very bad that year.’
His wand was 16 inches, and it was described as rather bendy
Given Hagrid’s immense size (he is half-giant, after all), it’s no wonder that his wand would follow suit. Sitting at an awe-inspiring 16 inches, the wand, which was made of oak, has also been described as rather bendy. According to Mr Ollivander's notes on Wand Woods, oak makes sense for Hagrid - as wizards who use oak wands usually have an 'affinity with the magic of the natural world' - which Hagrid definitely does.
Unfortunately, after his expulsion from Hogwarts in his third year, Hagrid's wand was broken. And, we think he’d prefer it if we kept away any mention of his pink umbrella...
He can’t cast a Patronus
Given his affinity for creatures, it was surprising to learn that Hagrid can’t actually cast the charm to produce an animal guardian. In a Q&A with Harry Potter fans on Twitter, J.K. Rowling was quizzed what Hagrid’s Patronus would be. In reply, she wrote, ‘Hagrid couldn't produce a Patronus. It's a very difficult spell.'
Hagrid is resistant to stunning spells (which is probably due to his size and strength)
Most likely owing to his huge size, and his status as a half-giant, Hagrid is pretty resistant to stunning spells. As Herminone explains in Harry Potter and the Order of the Phoenix, ‘It’s very hard to Stun a giant, they’re like trolls, really tough.’