By Dream crossing I mean the ability to enter another person's dreams whether to just observe or to maybe to change the dream in different ways.
I also want to know if any consequences like
1:Your mind being tricked making you believe it's real
2:You could actually be hurt by the dream
3:You could get trapped in the dream
4:You could damage your or the other persons mind
Could happen
Finally, just to point out I am not thinking of manipulating anyone or anything like that I merely think this could be used for fun (by that I mean you and someone else seeing what the other could dream up and maybe have a battle)
I know this sounds very unrealistic, but I have a really big imagination.
Entering other' dreams is a matter of belief. Most of your list is not really a possibility, however, except the first. That is all any sort of projection really is: believing your consciousness is going somewhere.
What I've heard from those who do believe in projecting into other people's dreams:
*The other person must actually be dreaming at the time, not just sleeping. This can make timing incredibly difficult.
*Most dreams are forgotten. So even if it 'does work,' don't be surprised if the other person does not recall the experience.
*If the person wakes up, your attempt is over.
In the incredibly rare instances of shared gnosis on the topic:
*The message of the person entering another's dream may be distorted, if it is even conveyed.
*The persons unvolved may appear completely differently within the dream, or be unrecognizable.
*The dreamer may only remember 'I had a dream about you last night' and nothing more ... If that much.
Some people who practice this belief say that it cannot be dokne during meditation; that the person trying to enter another person's dream must be asleep and dreaming in order to project into another dream -- that is, to attempt something like astral projection surfing sleep. So lucid dreaming is mandatory according to those.
Some others say it's very similar to astral projection, but with a different destination.
Even if you can do it, I wouldn't because dreams are a way for a person to work out their problems. Its also how their subconscious speaks to them. That's why people say "you should sleep on it."