How can I make Mario Style PowerUps?

I am currently creating a game in Unity 3D and I wanted to make it more exciting. I want to create a Mario Style PowerUp which can make the character bigger. I am guessing that it has something to do with triggers and colliders, but i am missing a script that can make the character grow bigger, I think.
Once again i am trying to create a PowerUp that makes my character bigger. If coding is required please tell me if it is JavaScript of CSharp and paste it in you comment.
Thanks in Advance Everyone!

There’s many ways to do that. The most obvious one is to change the localScale of you char when it collides with the power up.

Something like:

public class PowerUpper : MonoBehaviour {
    void OnTriggerEnter(Collider other) {
        if (other.name = "PowerUp") {
            gameObject.localScale = new Vector3(2, 2, 2);
        }
    }
}