Can you guys help, I basically want to collide 2 game objects to initiate the third one, for example when I drag the pasta on plate these two object will destroy then pasta outcome will initiate..

Questions & Answers
1

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

public class Manager : Singleton
{
protected Manager() { } // guarantee this will be always a singleton only - can’t use the constructor!

public GameObject Plate;
public GameObject Pasta;
public GameObject PastaOutcome;

public void InstantiateNewCube(MyCubeClass cubeOne, MyCubeClass cubetwo, Vector3 position)
{
    if (cubeOne.color == "blue" && cubetwo.color == "yellow")
    {
        Instantiate(greenCube, position, Quaternion.identity);
    }

    //you need more methodes here for each fusion scenario of colors
}

}//the code is not mine, I just use it as reference

2

Use methods OnCollisionEnter, or OnColliderEnter, 2d or 3d