have bats in (one's) belfry
To be crazy; to act, think, or behave in a foolish or nonsensical manner. Tommy has bats in his belfry if he thinks he can convince our mother to let him get a tattoo for his birthday. There's an old lady who stands on the corner yelling at strangers all day. I think she might have bats in her belfry.
have bats in one’s belfry
(...ˈbɛlfri) tv. to be crazy. (see also bats. Have got can replace have.) Pay no attention to her. She has bats in her belfry.