It's ice! I guess moisture got in there since there was no hose clamp (not sure who did work on this car before I owned it
), collected, and froze. I'm thinking this has to be the cause. Still planning on replacing the fuel pressure regulator.
EDIT: Is that a coolant hose by any chance? It's orange, like coolant, so I'm wondering if it's possible that it got so cold here that it froze even the antifreeze? It's been in the negatives (-15 to -20) here lately.