Możesz zrobić np. tak:
using UnityEngine;
using System.Collections;
public class zrobParticle : MonoBehaviour {
public GameObject particleWybuchu;
// Use this for initialization
void Start () {
}
// Update is called once per frame
void Update () {
}
void OnCollisionEnter()
{
Instantiate(particleWybuchu, this.transform.position, this.transform.rotation);
}
}