SpriteKit - Change Animation at SKPhysicsContact - animation

Question

I am very new to Sprite Kit game development. I am currently developing my first game - a simple game where the player must navigate a simple object past obstacles. If the object collides with an obstacle - GAME OVER.
I got that to work fine but I have been stuck for over a week on an animation problem. I've literally searched for an answer for days now ... without success. So basically ... when my object is being navigated past the obstacles I have one animation pattern (that works fine). Once it hits an obstacle however, I want the animation pattern to change (into an explosion). And for some reason that is NOT HAPPENING! :( It is basically completely IGNORING the two lines of code ([self stopBeeAnimation]; and [self defeatedAnimation];) I added and the game is over right away.
Any help I might get on this, is really appreciated (this is driving me nuts) :)
Thank you so much.
Here my code:
-(void)didBeginContact:(SKPhysicsContact *)contact {
SKSpriteNode *firstSprite;
SKSpriteNode *secondSprite;
firstSprite = (SKSpriteNode *)contact.bodyA.node;
secondSprite = (SKSpriteNode *)contact.bodyB.node;
if ((contact.bodyA.categoryBitMask == beeCategory) && (contact.bodyB.categoryBitMask = obstacleCategory)) {
[self stopBeeAnimation];
[self defeatedAnimation];
[obstacleArray removeAllObjects];
[bee.physicsBody setAffectedByGravity:NO];
[timer invalidate];
scoreLabel.fontSize = 30;
scoreLabel.text = [NSString stringWithFormat:#"GAME OVER %d", score/2];
[self removeFromParent];
SKTransition *transition = [SKTransition fadeWithDuration:5];
[self.scene.view presentScene:[[NPMyScene alloc]initWithSize:self.size] transition:transition];
}}
and:
-(void) defeatedAnimation {
SKAction *defeatedAnimation;
NSMutableArray *textures2 =[NSMutableArray arrayWithCapacity:5];
for (int a = 1; a < 6; a++) {
NSString *textureName2 = [NSString stringWithFormat:#"defeated%d", a];
SKTexture *texture2 = [SKTexture textureWithImageNamed:textureName2];
[textures2 addObject:texture2];
}
defeatedAnimation = [SKAction animateWithTextures:textures2 timePerFrame:0.2];
}

Answer 1

Look here:
SKTransition *transition = [SKTransition fadeWithDuration:5];
[self.scene.view presentScene:[[NPMyScene alloc]initWithSize:self.size] transition:transition];
You're presenting a different scene (or maybe another instance of the same scene class?) in the view after trying to run your animations. Any animation changes in the current scene won't be visible because the new scene replaces the current scene.
But even before that...
- (void)defeatedAnimation {
// ...
defeatedAnimation = [SKAction animateWithTextures:textures2 timePerFrame:0.2];
}
You're creating an SKAction but not doing anything with it. For an action to take effect you need to run it on a node with runAction:.