My enemy ai won't stay on the ground help please

I am having a problem with my enemy ai . Whenever I click on play the enemy ai go in the air move toward the player ' when the player is in distance. I also have some animations attach to the enemy ai and I have all of them on loop . I think their is something wrong with my code . I just want the enemy to stay on the ground and the animations to play. Here is my C # script. Help would be appreciated.

using UnityEngine; using System.Collections;

public class an : MonoBehaviour { //nav mesh agent needed public Transform target; public float Distance; public float rotationdamping; public float moveSpeed ;

 void Start () {
 
 }
 
 
 void Update () {
 
 Distance = Vector3.Distance (target.position, transform.position);
 
 if (Distance < 4f)
 {

     watchplayer();
 }
 
 if(Distance < 3f)
 {
     if(Distance > 2f)
     {
         follow();
     }
 
     else if(Distance < 2f)
     {
         attackmode();
     }
 
 }
 
 }
 
 void watchplayer()
 {
     Quaternion rotation = Quaternion.LookRotation (target.position - transform.position);
     transform.rotation = Quaternion.Slerp(transform.rotation, rotation, Time.deltaTime * rotationdamping);
     GetComponent<Animation>().Play("idle");
 }

 void follow()
 {

     transform.Translate(moveSpeed * Vector3.forward * Time.deltaTime);
     GetComponent<Animation>().Play("move");
 }

 void attackmode()
 {
     
     GetComponent<Animation>().Play("attack");
 }

}