Madness string 1941

Random mermaid
This yellow line down the center of my field of vision? It's just this line, slightly askew, marking the boundary between inside and out. It's perfectly real.

Eh, you're probably actually the figment of someone else's dream. When they wake up, you'll just go poof. If you now feel existential dread, congratulations! You're probably awake. (But you could still be the dream of a dread god.)