take it into (one's) head (to do something)
To decide or become set on the idea to do something, often something capricious. Jane has taken it into her head to become a glassblower, and she's already ordered all the tools.
take it into your head
If somebody takes it into their head to do something, especially something strange or foolish, they suddenly decide to do it. He suddenly took it into his head to go out to Australia to stay with his son.
take it into your head to do something
decide impetuously to do something. 1991 Ben Okri The Famished Road Fearing that the supervisor might notice me as well and take it into his head to order me to break my neck carrying cement bags, I hurried on.
take it into your head to do something
suddenly decide to do something: She’s taken it into her head to give all her books away.