Leviticus 19:31 - Regard not them that have familiar spirits, neither seek after wizards, to be defiled by them: I am the LORD your God.
Leviticus 20:6 - And the soul that turneth after such as have familiar spirits, and after wizards, to go a whoring after them, I will even set my face against that soul, and will cut him off from among his people.
1 Chronicles 10:13-14 - So Saul died for his transgression which he committed against the LORD, even against the word of the LORD, which he kept not, and also for asking counsel of one that had a familiar spirit, to enquire of it...
Just to name a few verses in the Scriptures.
People who dabble in the spirit world (seances, ouija boards, etc.) are inviting evil into their lives. They are opening a door and letting anything walk in; evil forces look for these openings.
They are foolish. Most are not prepared for what can come through.
People need to stay far away from this and stay close to God.