Error: "-1.#.ND" ? What?

[palistov]

The -1#ND thing has to do with floating point limits I think. You're probably flying down very fast. See, it looks like you have two bodies on your entity there, right? Only use one. The player is likely colliding between two of them at the same time when walking over the rock and accumulating an extremely high force from the bodies trying to push the player out of them both at the same time. Then you fly off and die because there is a minimum Z value you have to have to play.

Edit: For a rock like that you don't even need it to be an entity, you can just load it into your map through the editor as a static object. The engine constructs a collider from the mesh for you, so you can walk over it.