You need to show your codes. Cannot help, otherwise.

sorry I guess I forgot to put it up, I hope you don't mind me putting up everything I have I just don't know what's causing the problem public class Blob extends Actor { public void act() { move(2); turn(1); checkKeys(); Actor coin = getOneIntersectingObject(Coin.class); if(coin!=null) { World myWorld = getWorld(); myWorld.removeObject(coin); Sky sky = (Sky)myWorld; } // If we are touching a pipe, then Game over if (getOneIntersectingObject(SpaceBug.class) !=null) { displayGameOver(); } } private void displayGameOver () { GameOver gameOver = new GameOver(); getWorld().addObject(gameOver, getWorld().getWidth()/2,getWorld().getHeight()/2); } private void checkKeys() { if(Greenfoot. isKeyDown("left")){ setLocation(getX() - 1, getY()); } if(Greenfoot.isKeyDown("right")){ setLocation(getX() + 1, getY()); } if(Greenfoot.isKeyDown("up")){ setLocation(getX(), getY() - 1); } if(Greenfoot.isKeyDown("down")){ setLocation(getX(), getY() +1); } } } public void act() { move(Greenfoot.getRandomNumber(5)); turn(Greenfoot.getRandomNumber(20) - 10); if(getX()==0) { setLocation(getWorld().getWidth(), getY()); } if(getX()==getWorld().getWidth()-2) { setLocation(0, getY()); } if(getY()==1) { setLocation(getX(), getWorld().getHeight()); } if(getY()==getWorld().getHeight()) { setLocation(getX(), 0); } } } public class Sky extends World { int coinCounter = 0; int blobCounter = 0; int score = 0; int FIRST_COIN = 240; Score scoreObj = null; /** * Constructor for objects of class MyWorld. * */ public Sky() { // Create a new world with 600x400 cells with a cell size of 1x1 pixels. super(800, 600, 1); prepare(); } public void act() { coinCounter++; if (coinCounter % 100 == 0) { createCoin(); } if (coinCounter >= FIRST_COIN) { if (blobCounter % 100 == 0) { score++; scoreObj.setScore(score); } blobCounter++; } } private void createCoin() { //Create Coin Object Coin coin = new Coin(); } private void prepare() { // set paint order setPaintOrder(GameOver.class, Score.class, Blob.class, SpaceBug.class); //Create a Blob Object Blob blob = new Blob(); //Add Blob to our world addObject (blob, 35, 300); //Add a coin to the world Coin coin = new Coin(); addObject(coin, 0, Greenfoot.getRandomNumber(getHeight())); //Add a SpaceBug to the edge of the world SpaceBug spaceBug = new SpaceBug(); int x = getWidth(); int y = Greenfoot.getRandomNumber(getHeight()); addObject(spaceBug,x,y); } } public class Score extends Actor { /** * Act - do whatever the Score wants to do. This method is called whenever * the 'Act' or 'Run' button gets pressed in the environment. */ //Constructor public Score() { GreenfootImage newImage = new GreenfootImage(50, 50); setImage(newImage); }// end score public void setScore(int score) { GreenfootImage newImage = getImage(); newImage.clear(); Font f = new Font("Arial",Font.PLAIN,32); newImage.setFont(f); Color c = new Color(127, 127, 127, 127); newImage.setColor(c); newImage.fill(); newImage.setColor(Color.black); newImage.drawString("" + score, 16, 36); setImage(newImage); } } public class GameOver extends Actor { /** * Act - do whatever the GameOver wants to do. This method is called whenever * the 'Act' or 'Run' button gets pressed in the environment. */ public void act() { // Add your action code here. } }