Hermione's first ever friend at Hogwarts turned out to be a little... Unusual.
Grog
Ten points each richer, Harry and Ron returned to the girls' loo they'd locked the troll in with McGonagall and Snape in tow, already hearing the troll grunting inside. McGonagall unlocked the door and stepped into the lavatory... Only to freeze.
The troll was sitting on the floor next to the sinks, and McGonagall's brightest – if a little isolated – first year Gryffindor girl was sitting right next to it, a tiny hand resting on the troll's enormous knees. "-but really, you should think about forming a union – oh, hello Professor!"
It was a credit to McGonagall's ability to maintain her composure that she didn't remain speechless for more than maybe five seconds. "Miss Granger?" she eventually managed to ask. "What are you-"
"Oh, I've missed the feast, haven't I? My apologies-" she looked down at her feet for a moment before continuing. "But I was a little... Upset-" she glared at Ron, who was peeking at her and the troll from behind Professor Snape. "-and needed some time alone. And when Grog came in-"
"Grog?" McGonagall asked faintly.
"Oh, I didn't introduce you, did I? How rude of me! I apologise, Professor." Hermione stood up and made an elaborate gesture indicating the troll. "Professor McGonagall, this is Grog," she said. "And Grog, this is Professor McGonagall." She beamed at them both, though only Grog was beaming back at Hermione, who was already talking again, as was her wont. "I've of course memorised Fantastic Beasts and Where to Find Them, so of course I knew trolls often work as security and even learned a bit of Trollish – I thought it might come in handy –, though I'm surprised we didn't see any of Hogwarts' security trolls until now."
"Hogwarts doesn't have security trolls, Miss Granger," Snape cut in at this point.
Hermione blinked. "Well, I'm pretty sure it has at least one." She nodded in Grog's direction. "Anyway, it was kind of boring to just sit here and feel sorry for myself, and Grog didn't really have anything in particular to do, so we started to chat."
"Herrrrmeeeoooneee nooooceeee!" Grog said, or rather shouted at this point, banging his giant club on the floor and leaving a sizable crater.
Hermione patted Grog's knee. "Thank you, Grog. So... That's pretty much it, really," she finished, once again addressing her Professors.
"I... See." McGonagall said after a few more moments of contemplation than were strictly necessary. "Nonetheless, I'm afraid that Hogwarts does not employ security trolls, and Mr... Grog... will have to leave."
"No!" Hermione shouted, slinging her arms around Grog's neck - or trying to, anyway. It was a big neck -, while the troll bashed another crater into the bathroom's floor to express his support for Hermione. "He's my best friend! And he likes me, too! A lot better than the strange man who ordered him to walk through the corridors without paying him!"
Snape's eyebrows rose up to his hairline upon receiving this piece of information, while the recently arrived Quirrell - who stood in everyone's back - choose this moment to quietly slink away rather than making a show of fainting again. Sure, he'd memory charmed the troll sufficiently to make identification impossible, but... Better safe than sorry.
"And besides," Hermione continued, "security trolls are very poorly paid, so I'm sure Hogwarts could afford to hire him." She actually looked a little angry for a moment. She and Grog had gone over mountain troll pay rates in considerable detail, and Hermione had been quite shocked by the degree of exploitation trolls were suffering from – as it turned out, trolls were usually in an excellent position to negotiate by way of clubbing, but they tended to forsake proper payment in favour of pig carcasses.
"Afford, maybe-"
"- or if you don't, I will!"
And so, Grog arrived at Hogwarts. Grog and Hermione quickly became inseparable, Ron Weasley's behaviour towards the bright first year rapidly improved, Draco Malfoy learned valuable lessons about keeping his mouth shut, and several months later, Hermione Granger, Marcus Flint and Grog received an award for their furthering of inter-house cooperation as Grog's budding friendship with the Slytherin Quidditch captain tore down the traditional barriers between Slytherins, Gryffindors, Muggle-borns and Purebloods alike.
A/N: Kind of random, edited from the Spacebattles version