the snake body shakes uncontrollably when it's close to it's target it's rotating to. Not sure how to approach this problem next. vid here: http://youtu.be/rTrsRnpJ0to

SnakeBody_shakes_uncontrollably.cs

using UnityEngine;
using System.Collections;

public class SnakeBody : MonoBehaviour {

	private float moveSpeed = 5f;
	private float rotationSpeed = 10f;
	private Transform target;
	private Transform source;

	// Use this for initialization
	void Start () {
		source = transform.FindChild ("pivotFront");
		target = transform.parent.GetComponent<SnakePartsFollow>().head.FindChild("pivot").transform;
		Debug.Log ( source.rotation ) ;
	}
	
	// Update is called once per frame
	void Update () {



		// Find the difference vector pointing from the weapon to the cursor
		Vector3 diff = target.position - source.position;
		// Always normalize the difference vector before using Atan2 function
		diff.Normalize();
		
		// calculate the Z rotation angle using atan2
		// Atan2 will give you an angle in radians, so you
		// must use Rad2Deg constant to convert it to degrees
		float rotZ = Mathf.Atan2(-diff.x, diff.y) * Mathf.Rad2Deg;
		
		// now assign the roation using Euler angle function
		transform.rotation = Quaternion.Euler(0f,0f,rotZ);
	}
}