Can a Black Hole form inside a black hole?

This is a theory of mine about -Can a black hole be formed inside a black hole . As i am not a scholar of physics or have studied that much about black holes that as physicists , so i would like you guys to tell me if this is a possibility .

Black Holes are formed when the core of a dying star collapses under its own gravity to form a highly dense region in space devouring anything that gets in its way.

But a black hole can also be formed by compressing anything to such a limit that it is crushed under its own gravity and forms a black hole.

As black holes devour matter and matter falls into the black hole passing through the event horizon there is a slight chance that before it reaches the singularity , the matter is highly compressed under the gravity of the black hole that it forms an another black hole inside the black hole before it reaches the singularity.

There is a also a theory that suggests that we are living inside a black hole and if it is the case than it might a possibility that other black holes can form inside a black hole.

Well these all are the theories and who knows the reality might be totally different than what we think of it.