My dash looks like a teleport

So i’m making a dash in a spinning top game, it moves in the direction i want it to and at the speed i want it to but instead of looking like a dash it looks more like a teleport
Here’s the code I made ;

    using UnityEngine;
    using System.Collections;

    public class Dash2 : MonoBehaviour {

	public float speed = 10.0f ;
	// Use this for initialization
	void Start () {

	}
	
	// Update is called once per frame
	void Update () {
		if (Input.GetKeyDown (KeyCode.X)) {

			var move = new Vector3 (Input.GetAxis ("Vertical"), 0, Input.GetAxis ("Horizontal"));


			rigidbody.AddForce(transform.position += move * Time.deltaTime * speed );
			rigidbody.useGravity = true ;
	}
  }
}

Your AddForce method arguments make no sense. Either add to the position or add a force.

First, you probably want this before doing anything with the move variable

move = Vector3.ClampMagnitude(move,1);

Then, add force like so.

rigidbody.AddForce( move * force );

Note that adding a constant force (as you’re doing) in Update() is a bad idea. As a general rule, all input gathering goes in Update(), and all physics interactions belong in FixedUpdate().