verb

• (transitive) To fall on or spill over so as to cover (something).
  "But her laugh stuck in her throat, for at that moment a shadow overfell the two houses"
• (transitive) To change or affect so as to pervade (something); to come over
  "From thence King Hakon proceeded up the Dovrefield; but as he was going over the mountains he road all day after a ptarmigan, which flew up beside him , and in this chase a sickness overfell him, which ended in his death ; and he died on the mountains."
• (intransitive) To fall over; to spill from an edge or height.
  "I had arrived at this conclusion, and was meditating on my possible conduct under the circumstances, as I groped my way gingerly enough in the dark shadow of a long crumbling wall, where the ivy clustered and overfell, when round a slight bend, obscured by straggling bushes , I came upon the most unexpected and picturesque sight imaginable – that of a gipsy camp."
• (intransitive) To fall over; to topple.
  "Then back-toppling, crashing back – a dead weight flung out to wrack, Horse and riders overfell."