What is the definition of Birthday Weapon?

A 'birthday weapon' is like a superhero's secret weapon, but instead of a cape and flashy gadgets, it's just a silly thought that pops up on someone's mind every time they think about their birthday. It's a fun, lighthearted concept, but let's put on our thinking caps and give an unsettling example: "On his birthday, he couldn't stop blaming the cake for the existential crisis he felt - because who doesn't, right? It's like saying, 'My birthday weapon is my favorite chocolate chip cookie!' but with way more existential dread."