"Can't add script behaviour AICharacterControl. The script needs to derive from MonoBehaviour!" ?

I’m trying to make a typewriter-like text using another question on here but I keep on getting this pop-up saying I’m not able to do so. How do I fix it?

(EDIT)
All of my scripts are doing this within the project! I can’t find a way to fix it, and it makes it so I can’t work within it- I don’t want to get rid of all my progress so far, how do I fix it?

Here’s my script:

string[] vicinityText = new string[2]
    {
        "I see you're unfamiliar with this place... here's some basic enemies. Fight or die trying.",
        "Easy enough, right? Now let's test your mathematical knowledge."
    };

    public Text vicinityTalkBox;
    int currentTextDisplayed = 0;

    private void Awake()
    {
        StartCoroutine(AnimateText());
    }

    IEnumerator AnimateText()
    {
        for (int x = 0; x < vicinityText[currentTextDisplayed].Length + 1; x++)
        {
            vicinityTalkBox.text = vicinityText[currentTextDisplayed].Substring(0, x);
            yield return new WaitForSeconds(0.3f);
        }
    }

public class myScript: MonoBehavuour
Your script file should also be named myScript. These two should be equal

Okay, I fixed it! Turns out that importing only part of “Standard Assets” leaves your project kinda… well, broke. It’s solved!