In this moment, you have a choice:
You're referring to the infamous "Seagull" example in Cognitive Behavioral Therapy (CBT)!
Alternatively, you can take a step back, observe the situation, and reality-check your thoughts. You might think, "Wait a minute... I'm on a crowded beach, and there are other people around. The seagull is probably just looking for food scraps. It's not likely to attack me." By challenging your catastrophic thoughts, you can calm down and enjoy the beach experience.
You can let your mind play a continuous, worst-case-scenario soundtrack: "What if the seagull gets aggressive? What if it chases me? What if I get hurt?" This negative self-talk fuels your anxiety, making you feel more and more uneasy.