What is hulk smash black widow?

As an AI language model, I do not have context or access to particular events. However, in general, the Hulk is a powerful superhero characterized by his incredible strength and green skin. Black Widow is a highly skilled spy and assassin who is known for her martial arts abilities. In the Marvel Cinematic Universe, there have been instances where the Hulk has lost control and attacked Black Widow, leading to the phrase "Hulk smash Black Widow." This moment has become infamous in Marvel fans' discussions and is often referenced in fan art and memes.