The titmouse (Parus Major) found in some regions of Asia and North Africa is known as the most brutal bird in the world because it does not eat meat but eats the brains of its prey to survive, people have to call it the 'Zombie bird'.

The Great Titmouse is a gentle and lovely bird with smooth feathers and two white stripes on its cheeks. Its diet consists mainly of insects and small grass seeds. However, when food becomes extremely scarce in winter, the Great Titmouse cannot find enough food to feed itself and its young. In order to have enough food and survive, the Great Titmouse is forced to choose an extremely violent solution: killing other birds and even its own kind to eat.
With a savage killing instinct and an extremely powerful weapon, a steel-hard beak, the titmouse will tear out the brain of its prey and enjoy it deliciously. They do not eat meat but choose the brain because it is a soft, easily digestible and energy-rich part.

The Great Tit can hear the ultrasonic sounds made by bats. Therefore, one of the prey of the Great Tit is a species of cave bat. They often wait at the entrance of caves to catch some unfortunate bats.
In addition to bats, the great tit also hunts other birds and its own kind.
One of the reasons the great titmouse has become such a bloodthirsty killer is that seasons are becoming more severe and longer due to climate change.