two objects collides and 2nd is destroy and a new object appear,one object collide with other object other object destroy and a new object appear at another place

Questions & Answers
1

first only two objects shown in game and when one collide with other the other one destroyed and a new object will appear like in snake games.

,two objects are shown in the game one collide with other then other destroy and a new object appear like in snake games

2

This might help.

public Collider objectToHit;
void OnCollisionEnter(Collision col) {
    if(col == objectToHit) {
        //Move the object
        //Add score or something
    }
}