have (something) on the brain
to be obsessed with something
My sister has tennis on the brain and she is always talking about it.
Most Dangerous Dog Breeds
The Dogo Argentino is a large, white, muscular dog that was developed in Argentina primarily for the purpose of big game hunting, including wild boar and puma. Though extremely strong and athletic, the Dogo was bred to be non aggressive towards humans. Nevertheless, it is illegal to own a Dogo in the United Kingdom under their Dangerous Dogs Act of 1991.