"The Potter vaults have been guarded by a sphinx for generations," Griphook explained. "The Potters started the tradition on the grounds that any Potter who can't answer a few simple questions doesn't deserve access to the vault."
The sphinx smirked cheekily at Harry, as though she held assumptions about his worthiness.
"Ask away," Harry said to the creature.
The sphinx grinned and began.
"Who approaches the Potter vaults must answer me these questions three, ere the other side he see," she said.
"Ask me the questions, Miss Sphinx," Harry said. "I'm not afraid."
"What is your name?"
"Harry James Potter."
"What is your quest?"
"To inspect my family's vaults."
"What…is your favorite color?"
"Green."
"Right, off you go."
Harry looked at the sphinx curiously.
"Uh…thank you?"
The two men and the goblin then proceeded onwards.
"She always gives an easy question to the Potters," Griphook explained. "You should hear some of the things she asks others who have tried to get through to the vaults."
"Like what?"
"I believe she asked Albus Dumbledore what the air-speed velocity of an unladen swallow was."
"An African or European swallow?" asked Josiah.
Griphook smirked and shrugged.