there is MDEA which is 3,4-Methylendioxy-N-ethylamphetamine (which is extremely rare I believe), but since you have no further information, it could be anything really... you should also realize that drug dealers talk shit all the time.
Because they are dangerous? Or at the very least, potentially dangerous.
I don't know about you, but I put ingesting a drug that has very little known of its long term effects in the same boat as checking to see if you bled your car's brakes correctly by driving flat out at a wall and trying to stop before you hit it.
I understand what you meant, but you cannot deny the inherent danger that comes with taking something that hasn't been around long enough to say for certain what effect it has or how it works. Rolling that dice, in my mind, is synonymous with 'dangerous'.
Also, read more about MDMA. As the other guys said, MDMA is just like an RC - its fairly new in human use, thus we dont know the long term effects of it. We just CANT know because its so new. Newer chemicals are even more unsafe when it comes to this
To have GOOD data about a drug, hundreds of years are required, really. Psilicybin mushrooms and marijuana are examples of well documented drugs, with thousands of years of use.