The horse raced past the barn fell.
That’s a grammatically correct sentence. What does it mean? Most readers have to puzzle over it a bit before seeing the interpretation
The horse [that was] raced past the barn fell.
This is a “garden-path sentence” — the reader naturally assumes one interpretation and is confused to find that another had been intended. Further examples:
The old man the boat.
The government plans to raise taxes were defeated.
The cotton clothing is made of grows in Alabama.
I convinced her children are noisy.
Time flies like an arrow; fruit flies like a banana.
In writing, lexicographer Henry Fowler calls it “an obvious folly — so obvious that no one commits it wittingly except when surprise is designed to amuse. But writers are apt to forget that, if the false scent is there, it is no excuse to say they did not intend to lay it; it is their business to see that it is not there, and this requires more care than might be supposed.”