they think they are
Apenas consiguen un trabajo, se creen que son tus padres.
As soon as they get a job, they think they're your parents.
— Elefante (2003)
¿Quién demonios se creen que son?
Who the hell do they think they are?
— Viaje a las estrellas II: La ira de Khan (1982)
¿Quién se creen que son para desobedecer una orden mía?
Who do they think they are, disobeying one of my orders?
— La Caída (2004)