Communication trough planes is based on the power of spiritual energy for the connection. The consumption of other sources of energy like heat or light are in most of the cases needed to maintain a fluent connection and it's the reason for the location of getting darker and colder. Or from initial apparitions to appear as dark shadows or abstract dark shapes.
Concept illustration created for my project The Book of The Forgotten
Yes. it's like a vagina. What you thought a vagina was. It's a portal to this world.