Blink in Sprite Kit

Use SKAction, colorizeWithColor method.

Example

Implemented in SKSpriteNode
When tapping node, blink event are invoked.

CharacterNode.h

@interface CharacterNode : SKSpriteNode
@end

CharacterNode.m

@implementation CharacterNode

- (instancetype)init {
    if(self = [super initWithImageNamed:@"character"]){
        self.userInteractionEnabled = YES; // Interaction YES, you can handle touch events
    }
    return self;
}

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    [self blink];
}

- (void)blink {
    SKAction *blinkCyan = [SKAction sequence:@[[SKAction colorizeWithColor:[UIColor cyanColor] colorBlendFactor:1.0 duration:0.2], [SKAction waitForDuration:0.1], [SKAction colorizeWithColorBlendFactor:0.0 duration:0.2]]];
    [self runAction:blinkCyan];
}