int r = arc4random() % 3;
    NSString* typeZ;

    if(r == 1) {
        typeZ = @"zombie";
    } else if(r == 2) {
        typeZ = @"raider";
    } else if(r == 3) {
        typeZ = @"mothership";
    }

    Enemy* anEnemy = [Enemy createEnemy:typeZ];


... depois...




        enemyShotOnceAlready = NO;
        NSLog(baseImage);
        theBaseImage = baseImage;
        NSLog(theBaseImage);
        enemySprite = [CCSprite spriteWithFile:[NSString stringWithFormat:@"%@.png", theBaseImage]];
        [self addChild:enemySprite];
        enemySprite.position = ccp (0, 0);