I need a real physics enabled nail gun that can nail body parts and corpses to walls and such...
If you played F.E.A.R or Half Life 2, you'll know what nail gun I'm referring to.

Sounds difficult to do...I don't know if you can get a nail to stick into a body part and also into the wall without ripping the body to bits or not getting to the wall.

not possible, sorry to bring the bad news but the physics engine wouldnt allow it.

As carpet ninja said, it is not possible.

Unless, you wanted to do some crazy trick
that involves, the nail pulling the actor toward
the wall with negative mass particles.

But, it isn't economical.

Yeah, but wouldn't the body part quickly gib?

Probably.

At this time, sticking anything to anything else is impossible.

Otherwise we probably would have already had flammable objects. (BURN!)

No, it's possible. Just not to actors. Adjust depth for moar stickyness.