"I want a poisonous one," Tom said as they approached the entrance to the reptile shop in Knockturn Alley, because the Magical Menagerie did not carry snakes. Horatio's Horrendous Herpetofauna had taken Hermione quite a while to find, and she still wasn't sure if all the creatures were strictly licensed.
She said, "No promises." They opened the door and a blast of warm, humid air greeted them. A charmed statue of a hydra screeched their welcome into the dim shop, where the only lit areas were light sources above reptile tanks and cages. A short, thin, moustached man came around the corner.
"What're you looking for?" he addressed Hermione.
"Snakes, if you have them," Hermione began.
"Black mamba!" interrupted Tom. "Or king cobra. Unless you have an Occamy or an Ashwinder…"
"Nothing too dangerous, or expensive," Hermione finished.
The man looked at her with a bored expression. "This way," he said.
Tom scurried around, conversing with the snakes in Parseltongue. Hermione smiled innocently at the shopkeeper, who looked thunderstruck. "Runs in the family," she explained.
Tom peered into the mesh cage of a sunning rattlesnake. "Hey," he said to him. "Wake up."
The rattlesnake raised his head. "A Speaker?" he hissed to himself. "It's a magical human boy-creature. What does it want?"
"I'm looking for the right snake to become my familiar," said Tom. Then he decided, "But I can't have you- you're talking to me in the third person. That's too weird to get used to."
The adjacent tank contained a horned viper. "Don't pay attention to him," she hissed, half buried in the sand. "A human Speaker- what a rarity. I'd like to be your familiar."
"You are beautiful," Tom agreed, admiring her yellow scales and handsome horns.
She raised herself up further so he could see her while belly. "I am extremely poisonous," she continued, red forked tongue flicking out. "I could kill a person with one strike."
"Amazing," Tom agreed.
The viper preened. "Do you have an oasis, where you live?" she asked. "And the sand there is not too rough?"
"I don't have an oasis at all," said Tom apologetically.
She shrank back, scales making a rasping sound. "No oasis?"
Tom heard another voice behind him. "She's too high-maintenance," it said. He turned around to see a tiny emerald snake nodding at him.
"What are you?" Tom asked.
"That," the horned viper sniffed aristocratically, "is a commoner. A basic green garden snake. Don't waste your time."
"She's a liar," the garden snake retorted. "Her venom kills small rodents. The worst her bite'll give you is a headache."
"Really?" Tom said, a trifle disappointed. "Well, what can you do?"
"I am a boomslang," she said. "My skin is used in rare potions, and my venom is slow-acting but fatal to humans."
"You don't even have fangs!" the viper bit out. "You are clearly a garden snake."
"My fangs haven't grown in yet," said the snake doubtfully.
"Excuse me, sir?" Tom said in English to the shopkeeper. "What kind of snake is that?"
"It's a green garden snake," the shopkeeper replied warily.
"She insists that she is a boomslang," Tom informed him.
"Only male boomslangs are green in colour," the man said authoritatively.
Tom turned back to the little snake. "What did the keeper say?" she wanted to know.
"Sorry, you're a garden snake," Tom said.
She seemed to deflate, but then brightened up. "Perhaps I'm an eastern green mamba," she said. "Then my venom would kill in just thirty minutes. No good in potions ingredients though," she added.
Tom considered the plain little snake. She was very small- just long enough to wrap around his arm once. But she had exceptionally expressive, shining eyes, unlike the viper's cunning, slitted pupils. "How do you feel about coming with me?" he asked.
She tilted her head. "I'd like that."
"What do you eat?"
"She gets fed crickets, with a pair of forceps," the spiteful horned viper said derisively.
"Shush, you," said Tom, who was liking the viper less and less.
"Yeah, pick on somebody your own size," hissed the green garden snake.
"Hermione?" said Tom, switching to English. "I think I'll take her."
"I thought you wanted a poisonous one," Hermione said.
"That's okay," said Tom. "Can I take her out?"
When the shopkeeper placed the snake into Tom's cupped palms, she immediately slithered up his arm, curled around his ear, and nestled herself at the top of his head. "Oh, I like that," she said. "What should I call you, Speaker?"
"My name is Tom," he replied. "What's your name?"
"We don't have names," she said.
Tom watched Hermione pay for the snake, her cage, and a bag of crickets.
"I think I shall call you Estella," he told her.
The snake tested it. "Estella. Esssssstella," she hissed. "Estella, the eastern green mamba." She drew herself up, proudly perched in his hair. "It has a nice ring to it."