Updating this with The Master Cleanse (2016).
This is less horror than others on this list and has a playful, supernatural element to it. It reminds me in a lot of ways of Deep Dark with the physical manifestation of something mental/psychological happening. It's... Kinda weird.
Quote:The Master Cleanse centers on a heartbroken man who attends a spiritual retreat, only to discover that the course releases more than everyday toxins and traumatic experiences. (imdb)
This is less horror than others on this list and has a playful, supernatural element to it. It reminds me in a lot of ways of Deep Dark with the physical manifestation of something mental/psychological happening. It's... Kinda weird.