Theorem   Pier Paolo Pasolini  (1968; It,15) Silvana Magano, Terrence Stamp

https://www.youtube.com/watch?v=oCGVIg1ksYU

Written and directed by Pasolini Thoerem is themed about the divine and corrupt. 

Terence Stamp plays a mysterious otherworldly figure known only as 'the visitor' who appears in the lives of an upper middle class family in Milan.  Just as abruptly as he appeared he disappears with consequences for all those he has touched.  It's an exemplary, beautiful and strange doorway into the heart of Pasolini. Almost wordless, relying on camera frame and body language. 

This may or may not be of interest: https://www.maramarietta.com/the-arts/cinema/t-v/teorema/