🎮 Unity C# Basics: MonoBehaviour Guide

🤔 That Weird Word in Every Script

When I created my very first Unity script, I was excited to finally write some C#. I double-clicked it, opened it up, and there it was:

public class NewBehaviourScript : MonoBehaviour

{

void Start()

{

}

void Update()

{

}

}

At first, I honestly thought Unity was trolling me. Like, what even is a “MonoBehaviour”?

And why is it stuck to every single script I make? Turns out. it’s not optional fluff.

It’s the secret sauce that makes Unity scripts actually work.

🧩 So What Is MonoBehaviour?

Think of MonoBehaviour as your entry ticket to the Unity world.

Without it? Your script is just a plain old C# class, doing nothing.
With it? Your script suddenly:

• Can attach to GameObjects 🧱

• Can use Unity’s built-in magic (like Debug.Log(), Instantiate(), Destroy()) ✨

• Can respond to special Unity “lifecycle” events (like Start(), Update(), OnCollisionEnter()) ⏱️

Basically: MonoBehaviour is Unity’s bridge between your code and the game world.

🕹️ Start() and Update() in Action

The two functions you’ll meet first are Start() and Update().

void Start()
{
    Debug.Log("GameObject is awake! 👋");
}

void Update()
{
    Debug.Log("Frame updated! 🔄");
}

• Start() → Runs once when the GameObject is activated (perfect for setup code).

• Update() → Runs every single frame (great for continuous stuff like movement).

Think of Start() as turning on your console, and Update() as the game loop running every tick.

🚀 A Practical Example

Let’s make a cube move to the right:

using UnityEngine;

public class MoveCube : MonoBehaviour
{
    void Update()
    {
        transform.Translate(Vector3.right * Time.deltaTime);
    }
}

👉 Attach this to a cube.
👉 Press Play.
👉 Watch your cube slide like it’s on an invisible conveyor belt.

And just like that, you’ve used MonoBehaviour to control an object in your scene.

⚠️ Quick Things to Know

• Only MonoBehaviour scripts can be attached to GameObjects.

• You can write normal C# classes without it, but they won’t interact with Unity directly.

• Unity has dozens of other lifecycle methods (like OnCollisionEnter, OnTriggerEnter, Awake, etc.) — and they all come from MonoBehaviour.

  🎯 Wrapping Up

So yeah, MonoBehaviour isn’t some weird extra word Unity throws at you. It’s the foundation of every Unity script the thing that connects your code to the game world.