This is what I can remember about a movie that freaked me out when I was 7 years old. I saw in on TV, in Spanish… so, that may not help.
A brother and his sister are in the attic (?), laying on their stomachs, maybe in front of a mirror, drawing a squiggly version of this (which in my memory is way creepier and looks less like a confused, thin, Minion) with red crayons, chanting something along the lines of “Momma gay, give us your power”. (Momma gay, dans tu poder.)
The girl is sleeping and the brother places a hand held mirror in front of her face, which reveals the picture they drew. In what I assume was the final scene, the family is going somewhere, you have an eagle view of a yellow (?) car driving up the highway, among trees, and you hear the piercing scream of the girl, inferring she caught her reflection in the rearview mirror.
I’m 32 now. I remember I spent a week avoiding mirrors, and then only allowing certain parts of my body to be reflected, only a leg, or a hand at a time; running past mirrors, washing my hands with my eyes closed, opening my eyes real slow when I felt brave… And I’ve been looking for this movie, while not always wanting to find it, ever since.
Does it ring a bell?