Well, themes in 'bear attack fanfic' can vary widely. There could be the theme of fear and how characters cope with it during the attack. Additionally, the idea of adaptation to the wilderness might be present. For example, a character who is not used to the wild has to quickly learn how to deal with the bear attack situation, which may include finding shelter, using available resources to defend themselves, etc.
Love and acceptance are very common themes. Many gay bear fanfics focus on the journey of a character finding love and being accepted for who they are.
A common aspect in real bear attack stories is the presence of food. Sometimes people carry food while camping or hiking and bears are attracted to the smell. They might attack to get to the food source. Also, if a bear has cubs, like in the story from Siberia, it will be very protective. Any perceived threat to the cubs will lead to an attack. In addition, if a bear is sick or injured, it may also be more likely to attack as it may be more irritable or desperate for food.
One common theme is survival. Just like in Attack on Titan, the characters in these fanfics often have to fight for their lives against the Titans. For example, in many fanfics, the Hetalia characters use their unique skills to try and survive in this dangerous world.
One common theme is the exploration of Bakugou's hidden emotions. His tough exterior often hides a lot of internal turmoil, and panic attacks are a great way to expose that.
One common theme is the clash of different power systems. For example, when crossing over with a magic - based series, the contrast between the Titans' brute force and magic is explored.
One common theme could be the exploration of Conrad's inner turmoil. The panic attack often serves as a window into his deeper emotional and psychological state. It might also involve themes of recovery and how Conrad deals with the aftermath of the panic attack, like seeking support from friends or family.
One common theme is power struggle. Both 'Attack on Titan' and Marvel have characters with great powers. In the fanfics, it's often about how the powers from 'Attack on Titan' like the Titan - shifting abilities compare and interact with the superpowers in Marvel.
One common theme is loyalty. Pieck is often depicted as being loyal to her comrades and her cause. Another theme is sacrifice, as she is in a situation where she may have to give up a lot for the greater good.
One common theme is identity. The trans characters often struggle with their identity in a world full of danger like Attack on Titan. They have to come to terms with who they are while also fighting Titans.
Surprising a bear is a common cause. If a bear is startled by a human suddenly appearing in its territory, like near its den or while it's feeding, it may attack. Also, getting between a mother bear and her cubs is a very dangerous situation that can result in an attack. For example, in many backcountry bear attack stories, hikers unknowingly got too close to a mother with cubs and faced the bear's wrath.