Rob Kardashian's shocking Instagram post about his big sister, Kim Kardashian, was finally explained.

Last week Rob compared his sister Kim to a bloody screenshot of Amy Dunne (Rosamund Pike) from "Gone Girl."

The post remains up, but he hasn't posted anything since.

Apparently the post was Rob's way of calling Kim out for being two-faced, reported Us Weekly.

"Rob is in a dark place," an insider reportedly told Us. "Kim told him he needs to get out of his funk."

A second inside source confirmed this comment to Us, saying, "His post was about how she seems caring in public, but he feels ignored."