It is regrettably seldom discussed that there are many types of psychic absorption or trance. Some of them definitely are impure and thus allow uninvited spiritual entities to attach into the mind that is left weak and exposed. Getting one's mind into a random trance state is a sign of deviation and nothing else (see the first video).
Please note that this is exactly the same reason why anyone shouldn't be doing spiritual practices with drugs or alcohol: they make the mind unstable and spirit energetically weak. The exception is when doing cathartic rituals with psychoactive substances, e.g. ayahuasca, under a traditional and grounding supervision.
A crash course into Buddhism: Everything is mind. Frequencies of energy are entanglements to Six Lokas and Three Realms.
A crash course into Daoism from Buddhist point of view: Pure and safe cultivation in the Daoist sense is only accomplished in the Form and Formless realms, but in practice Form realm is preferred because it gives tangible bliss and purifies the body. The connection between From realms and the three Dantians has been expounded by Master Nan Huai Jin and his student William Bodri in case you need to discover more.
Correct instructions need to be followed, so that the proper Dhyana absorption is developed. Other trance realms are in the desire realm, hence automatically tainted with desires and emotional flotsam. In Qigong practices the danger is most pertinent in Spontaneous Qigong because this genre is not readily quiescent, may introduce wild emotions, requires adhering to exact instructions, and teacher's vigilant guidance. Artificial and forced stillness is another sure way to deviation when trying to train the mind.
Incorrect psychic absorptions induce deviations in person's energetic wiring, but few are wise enough to realize their mistakes. People chase after energetic sensations and quick shortcut empowerments unaware that these might be signs of short-circuit surging and not correct natural function at all.
In the field of psychic powers it's obvious that many people, who dabble while relying on their own prejudiced and warped intuition, exercise spiritual cultivation, but it's the impure spirit of ego and desires. Such deviation attracts codependent relationships with entities that may consciously promise or often unaware to the practitioner provide an easy access to supramundane knowledge and power. (I wish to comment that this is the original reason why both the Western Catholic and Eastern Orthodox Church have waged spiritual warfare against occult practitioners and pagans, although these days much has been said in the defense of the wrongfully persecuted innocents.)
A sensible reader might now ask what is the entity business exactly about. Think of a prison. You are bound there within the walls. There are dangerous competing gangs who have antisocial members and individualistic tough guys no one dares to challenge, and the both types are suffering from suppressed desires because they have to spend time imprisoned where their freedom and options are limited. Sometimes a new unaware guy goes through the prison system. There on the food line one of these gang recruiters or unassociated tough guys comes to them and says to them bluntly: Either become my prison prison bitch/punk and receive my protection or the other prisoners will kill you. Next thing you see the new guy dressed on stilt heels, wearing ripped jean shorts and busty tank top, and brandishing a full set of lipstick, mascara, long fake eye lashes, and dyed blonde hair. What prison does to some people is that they discover enjoying being the punk and surviving in that harsh environment in that fashion, so they keep following and justifying the lifestyle. The tragedy part is they remain unaware that they only were originally passing through and do not belong to the prison like the real inmates who scared and lured them into remaining. When the next new guy comes through, the self-realized busty blonde walks to welcome him and chirps: "Hey honey! You better become Bubba's bitch or you end up in the ditch. Want me to welcome you with a hug?"
Don't become anyone's punk or bitch. You are worth more.
Strive to realize independence, freedom, and clarity.
Don't expect too much, but be humble and skeptical of both yourself and others.