I haven't had many OBE's. Around 20, and in most of them it's very dark, I can barely move and they're not much fun. This one stood out and I've been wondering about it ever since.

It was night. I got vibrations and got out my body. I was above my bed and I couldn't move. I noticed two beings standing over my mothers bed. They had a humanoid outline, but were completely black. The edges of their silhouettes were very blurry, and it wasn't clear where their bodies ended. One of the beings had some sort of device (like a calculator), and it seemed like he was measuring something on my sleeping mother. The other one was just standing next to the first. The third being appeared to my left, and was about to continue to the right when he noticed me. He seemed surprised and interested when he saw me (judging from his body language, I couldn't see his face nor hear anything). He gestured to a fourth being to come and take a look at me. They approached me and one of them put his hand inside me. I couldn't avoid it, I couldn't move from the beginning. I thought, "Well ok, I'll let him, let's see what happens.", but it soon grew uncomfortable and I got scared so I started shaking to get back into my body.

Are such experiences common? Does anyone know who those beings are and what their purpose was? Is it possible that they are influencing my life in any way? Does their blackness symbolize evil?