Your opponent has some random straight draw that mighta turned into spades or just made a straight and he decided to go for max value because he thought you weren't folding on the river and he sucked out and didn't take the time to think about how much to bet.
Surely folding, it's interesting and not simple, but with basic analysis, seems like a simple fold. If he's doing this he'll try it again and you can adjust your calling range at that point. With no information, you should probably be the aggressor vs better players just because it's much harder for them to stand up to or manipulate than you being passive.
Fold and change your strategy to something more conducive for your skill vs the table's skill.