Mesh freaking out when moving bones So, I recently got into Blender and so far I'm having a lot of fun, even though it's really, really complicated. I've stumbled upon a few problems so far but most of them I have been able to solve. Expect for this one.

I'm testing my skills by trying to make a human, and right now I'm learning how to rig. I created the arm bones so far, but theres only one weird problem that I'm having. When I move the lower part of the arm, The whole human freaks out, as seen below:



Now first I though this had to do with the weight map, but after painting the body like this;



I still get a result that looks close to the previous image. As you can also see in the previous image is that it looks like as if the body exists of 2 inside each other (One part of the stomach stays still, the other one moves). However, when I look in edit mode there are no double edges, so im quite confused.

Does anyone know what causes this? Any help is much appreciated!

My .blend file can be found here:
This happens because couple of the vertices has very small weighting to the bones. So avoid this you need to select your mesh, then enter edit mode then select these vertices and set the weighting to 0 for the two bones as shown below:


This will fix the problem as shown below:

Updated .blend file can be found here: