This is what a friend told me:
When I was about sixteen I had a similar experience. Me and a friend were going at it for like three days straight, popping E like candy. Although E isn't really hallucinogenic in it's own right the sleep deprivation and other substances consumed (I really can't recall all of them, but codeine was among them) all added up that on the third day I started seeing things, dwarflike figures in the corner of my eye, fluffy ball making a round around the stereo.
I was alone with my friend in his living room wich was dimly lit and we were both looking at the ceiling when I noticed an amoebe-like thing floating thru the air, like when a spec of dust on your cornea when the lighting is right, but I could direct it with my mind, going up, down, left, right. After a minute or so I turned to my friend and said him what was happening, and his jaw dropped. He was having the exact same experience and when he pointed in the direction he was seeing it he pointed at the place where my "amoebe" floated around.
I actually almost forgot about this experience untill I saw this thread.
On a final note I'd like to ad that although these sessions were great fun, I now no longer partake in that kind of autodestructive behavior. Also, E just isn't that good quality anymore.

"I would never die for my beliefs because I might be wrong."
and
"Sanity calms, but madness is more interesting."
Bertrand Russell
All things are possible, everything is permissable