SlimeController.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class SlimeController : MonoBehaviour {

    public float moveSpeed;
    private Rigidbody2D myRigidbody;
    private bool moving;
    private float timeBetweenMove;
    private float timeBetweenMoveCounter;
    private float timeToMove;
    private float timeToMoveCounter;
    private Vector3 moveDirection;


    // Use this for initialization
    void Start()
    {
        myRigidbody = GetComponent<Rigidbody2D>();
        timeBetweenMoveCounter = timeBetweenMove;
        timeToMoveCounter = timeToMove;
    }

    // Update is called once per frame
    void Update()
    {
        if (moving)
        {
            timeToMoveCounter -= Time.deltaTime;
            myRigidbody.velocity = moveDirection;

            if(timeToMoveCounter < 0f)
            {
                moving = false;
                timeBetweenMoveCounter = timeToMove;
            }
        } 
        else 
        {
            timeBetweenMoveCounter -= Time.deltaTime;
            myRigidbody.velocity = Vector2.zero;
            if(timeBetweenMoveCounter< 0f)
        
            moving = true;
            timeToMoveCounter = timeToMove;

            moveDirection = new Vector3(Random.Range(-1f, 1f) * moveSpeed, Random.Range(-1f, 1f) * moveSpeed, 0f);
        }
    }
}