This is the 4th song off Lil Gnars debut mixtape “Gnar Lif3”.
The title of the song plays on the name of the superhero Batman changin the “man” for “mane”, a commonly used word in hip hop and slang in general which has the same meaning.

Often in rap, artists refer to themselves as “Bruce Wayne” to flaunt their riches. This is because Bruce Wayne, the real identity of Batman, is a very rich billionaire. Also Bruce Wayne rhymes with Batmane.