Batman: Hush

Selina Kyle calls one of her pet cats "Eartha." This is an in-joke/reference to Eartha Kitt who played Catwoman in the third and last season of Batman (1966).

Batman wears his black and gray costume for a short while in the opening act of the movie, after which he dons a costume where his cape, boots, gloves, and cowl are blue. When Batman chases Catwoman in the opening act, Batman is shown wearing his blue and gray suit for a few frames, before the camera cuts and he's shown to be wearing the black and gray suit again.

Featured in Everything Wrong with...: Everything Wrong With Batman: Hush In 16 Minutes Or Less (2019)