Thought

"You can still see the scars where those brains attacked me!"

— Ron Weasley regarding the brains in the Brain Room

The Tank of Brains, found in the Brain Room

Thought is an arrangement of ideas created by the brain which allows people to think. There is no real understanding of how it works or how to define it.

Occlumency

Occlumency was a type of magic that protected one's thoughts from Legilimency by teaching one to clear your mind and make it blank and empty, free of emotion and thought.

The Crown of Mneme

The Crown of Mneme was a legendary magical artefact of immense power that allowed the wearer to project their thoughts, memories and emotions onto others for the purpose of mind control. It was created by the Japanese wizard Dai Ryusaki.

British Ministry of Magic

In the Department of Mysteries, the Ministry of Magic studied thought by keeping brains in a tank of green liquid where they swam. As part of their studies, they could use magic to retrieve thoughts, which created tentacles of memories which looked like ribbons of moving images. When the tentacles touched someone, they were capable of hurting them by wrapping their tentacles around them.

During the 1990–1991 school year, Professor Olivia Green told Jacob's sibling that she could not hear them over her thoughts, whilst talking about her old job as an Unspeakable. This implied an association with the Brain Room.

Battle of the Department of Mysteries

"According to Madam Pomfrey, thoughts could leave deeper scarring than almost anything else, though since she had started applying copious amounts of Dr Ubbly's Oblivious Unction, there seemed to be some improvement."

— Ron Weasley's treatment after being attacked by thought

In the Battle of the Department of Mysteries, Dumbledore's Army and the Death Eaters fought in the Brain Room. When Ron Weasley was hit with a spell that left him mentally confused, he thought the brains looked funny and summoned them. When the thoughts soared at him, they started to wrap themselves around Ron's arms, nearly suffocating him. When the battle ended, Madam Pomfrey said that it would leave a scar, since nothing left deeper scarring than thoughts.

Appearances

• Harry Potter and the Order of the Phoenix (First appearance)
• Harry Potter and the Half-Blood Prince (Mentioned only)
• Harry Potter: Hogwarts Mystery (Mentioned only)