Make Game Object not move when hit

OK, I've been trying to figure this out for a few days now and I haven't found any answers. I'm making a space shooter, so all gameobjects have gravity unchecked. I'm trying to make an obstacle, that when the player hits it you just stop, the obstacle doesn't move. I have a rigidbody, I have the freeze position Z, and all the Freeze Rotation checked, but when you bump into it, it still moves. I also have mass at 1, and drag, and angular drag at Infinity. I do have a box collider.

Now what...

Make Game Object not move when hit