The Bible teaches that after death a person: returns to dust (Psalms 104:29), knows nothing (Ecclesiastes 9:5), possesses no mental powers (Psalms 146:4), has nothing to do with anything on earth (Ecclesiastes 9:6), does not live (2 Kings 20:1), waits in the grave (Job 17:13), and continues not (Job 14:1, 2) till the Resurrection. There is no consciousness of time in death (2 Corinthians 5:6-8), so for the believers, the next conscious thought from death is their awareness of their glorified bodies at Christ’s coming. The dead will sleep until the great day of the Lord at the end of the world (1 Thessalonians 4:16, 17; 1 Corinthians 15:51-53). They will receive their rewards at the second coming and not at death (Revelation 22:12). For more on the state of the dead, check the following link: https://bibleask.org/bible-answers/112-the-intermediate-state/
So, who are these entities that appear to people?
The Bible teaches that evil angels impersonate the dead and appear to the living to lead them astray. For “Satan himself transforms himself into an angel of light” (2 Corinthians 11:14-15) and, even as Christ Himself (Matthew 24:23, 24). And it is through these “spirits of devils, working miracles” (Revelation 16:14; 18:23) that pose as spirits of the dead that the devil will deceive the world. Demons may even give positive and true information to gain the trust of people and divert their attention away from God (John 10:10).
God warns His children saying, “And when they say to you, “Seek those who are mediums and wizards, who whisper and mutter,” should not a people seek their God? Should they seek the dead on behalf of the living?” (Isaiah 8:19). Since “the dead know nothing” (Eccl. 9:5), it is obvious that they cannot be consulted, and any effort at contacting them will lead to deception.
When people yield their wills to these demonic entities, they can get possessed by them as in the story of the demoniac (Mark 5:1-20). But praise the Lord there is hope for these afflicted ones. For when the demoniac that was tied with chains to the tombs went to the Jesus for deliverance, the Lord set him free from oppression and restored his mind.
In His service,