If you enjoyed the Exorcist films, the Rite, Fallen, or the Conjuring this might be something you'll enjoy.

It's the story of a grieving atheist telejournalist/author who bitterly goes in search of "proof" of the existence of God, after his beloved Christian wife is killed in a horrible freak accident. He decides that finding proof of Satan and demons would be more expedient than proof of angels and God.
The plot follows his attempt to invoke demons which includes the use of Satanic rituals, and powerful, dangerous hard drugs like LSD, ketamine, DMT etc.

What I liked about the movie is that it is a cautionary tale about taking Satan and demons casually. It is exactly the opposite of so many Hollywood movies which portray the use of dangerous narcotics like those mentioned above, as being no big deal.

The film also illustrates a Biblical warning (also found in the texts of other religions such as Vedantism and Buddhism) not to become too preoccupied with the occult and evil for any reason. There is wisdom in that.

CAUTION: As the Exorcist, this is not a movie for impressionable young people. There is a lot of very disturbing imagery, violence and profanity. It is not for people with delicate sensibilities.

The far left too often minimizes the dangers of both illegal drugs and with Satanism, often romanticizing evil and wickedness instead of warning against it. Seeing this movie might be good for any atheist who is leaning toward consideration of a similar path - casually inviting a demon into one's mind, for instance - particularly if it involved powerful drugs.

As a rule it is wiser to go looking for evidence of God than Satan, because by the time one has found what one is seeking in the latter case, one may wish one had never done so.

This can be found on Netflix or at many public libraries for free.