SomethingViewController.h

// ...
@property IBOutlet UIButton *button; // Connects the interface to the class. Can now alter the button with the button var.

- (void)disappear;

SomethingViewController.m

// ...
- (void)viewDidLoad { // We get this method for free on all view controllers.
  //So when the view loads in to memory...
  [_button addTarget:self action:@selector(disappear) forControlEvents:UIControlEventTouchUpInside];
}

- (void)disappear {
  _button.visible = NO;
}