What is the definition of Portal Fear?

"Portal fear" is the collective terror that sets your brain on fire when you think about the idea of stepping through a doorway to another dimension, time, or perhaps a parallel universe. It's the fear of the unknown, where every shadow could be an alien and every whisper could be a warning. Picture this: "The portal fear was so intense, I nearly forgot to breathe before I'd decided to cross it to see if my grandpa's ghost was actually out there, just to make sure I didn't accidentally invite a time-traveling bear into my living room."