Has anyone, through the practice of concentration on the ajña cakra, sustaining its beej, acquired any interesting power?

One year ago, after finishing one of these sessions I went to sleep. I dreamt very strange dreams. First I dreamt I had broken my roomates Mac (ok, not that weird, except it was a very lucid dream). Then I entered another lucid dream where a lot of things happened (the details are not important here), but when I woke up, although there were nothing significatively uncommon about the dreams I kept them in my mind as something uncomfortable. Then: When my roomate woke up he told me he past the first hours of the night (while I was sleeping) trying to fix his notebook believing he had broken it. I decided to make a test then and I asked him "Have you dreamt such and such things?" and proceeded narrating him the whole dream I "had". He confirmed, after first moments of shock, having dreamt exactly what I was telling him. As I had not told him the whole history I asked him to tell me more about the details of the dream and his report matched completely the rest of the dream.

Before that I was completely skeptical about siddhis or any "paranormal" stuff. After that I wasn't able to meditate for months. I got distracted and had many lustful desires, plus desires of using intoxicants, I wonder if in that experience, instead of we been sharing dreams, I had "entered" in his mind and somehow got "infected" with his thoughts and personality.

I've never tried this kind of meditation again, mainly because I don't think I'm ready to use it in a skillful way. But I do think this kind of practice can provide benefits¹. Does anyone here have practice "opening" the ajña cakra and knows how to develop it in a positive way?

¹ I wonder, for example, if the ability of "entering" the mind of people who have higher attainments (like fruitions) may provide energy for those pursuing enlightenment, as they got a chance to see the peace that comes with advancing on the path. (Then I have envisaged a whole new transmissions system, in which aspirants may "fish" attainments of those who have fully fullfilled the path and conversely arahants could "drop" the fruition in puthujjanas minds. With the advantage that this practice seems to be easy to do, easier than jhanas, so accessible to more people - I don't know however if it's easy to master)

I don't think there's anything special about the third eye chakra, I think its moreso linked to the a&p nana, which I would actually relate to the awakening of kundalini at the base chakra.  Unrelated to that, the a&p is likely to stimulate senations of a variety of chakras, depending on person, context, etc.

Beyond that, I would say that siddhi's are specifically linked to the a&p.  My first a&p was at a retreat in which I was able to call up various inexplicable synchronicities.  I have heard of other's doing the same.  I would guess that they pass and do not return for most.

Not trying to nay-say or reduce your experience here; I actually find the subject fascinating.

The transmission of enlightened states from master to pupil seems to be quite common in espteric traditions, eastern and western.

There are tens possible reasons for having the same dream, or thinking you've had the same dream, that do not involve the siddhis or anything supernatural at all. From having seen the same scene on the TV, to false memories, to confirmation bias (focusing on the similarities of the dreams instead of the differences) to archetypes (most people's dreams are very similar anyway). And on, and on, and on.

Man, I'm not in the position to prove anything and my first thoughts were "It must have any Freudian explanation I don't know". But the fact is that it wasn't something like "we both dreamt with snakes". We had literaly the same dream with all its details (we were both there, me and my friend, in "both" dreams, in the same place - a hut he owns in the countryside. We were able to identify the same people (and unable to identify the same amount of people), and describe the same little incidents (the presence of two blond yet tanned male twins -not identifiable-, one of which was raped by a mob in the shower - I never said it wasn't a weird unpleasant dream -, the arrival of my friend's mother in a car, and then we running naked up the hill, which became higher as we climbed it, as the perspective of "the dreamer" changed from first-person to a third person who stood flying above. I'm mean, there's too many specific details not to be impressed with, and not a single difference. Plus the fact that I let my friend report part of the dream (I didn't just told him as he agreed, I wanted to be sure he wasn't kidding), and the fact that I had earlier that night dreamt about what he was doing (trying to fix his notebook) in the other room.

But that's not the point anyway, my question was directed towards people who have experienced something similar through the practice of this particular (non-Buddhist) meditation, and found out if there's any utility in developing it.

(sorry, english is not my first language)

(But I agree with that one must always doubt its recollections and be aware of cognitive biases)

I have tendencies in this direction.  I think how things manifest may have to do with personality.  When I was at TMI (Monroe Inst, kind of like a meditation place with auditory technology assistance), I started dreaming other people's dreams.  Maybe it was the group energy thing and all of us doing the mind exercises at the same times throughout the day.  By the end, I figured it out and started asking the other ones if they had the same dream experiences and many little details would match.  One woman  had injured her back and then someone had volunteered to adjust it for her, and he only made it far worse.  I dreamt that experience she had, which in that case was a real event that happened some days before.  Another had a dream about a house up in the mountains with certain features.  Another had a dream that he was talking with all of us about a certain focus level that he had come up with himself.  I saw all those dreams plus a bunch others.  Instead of dreaming my dreams, I dreamt mostly other people's dreams and images.  For what can be learned, you can learn a lot more about how other people work and think, which I think contributes to metta, but I don't see much obvious benefit otherwise, assuming one is not the type to try to con or manipulate others.  Plus a lot of the stuff you get from other people is going to be negative and/or dark, it's not like it's all fluff and angels and light.  So although interesting in one way, it's not the epitomy of fun either.   I have not done another retreat like that and don't often meditate with others, but have gotten occasionally some flashes of that the few times I have at other places as well.  Something about group meditation sometimes makes that connection for me.  

-Eva