NOTE: May be metaphorical.
The building crumpled after the explosion.
The cookie crumpled in my hands.
WordNet 3.0 Sense Numbers: 1
His knees crumpled and he sat down.
She crumpled her lips together.
This fabric won't crumple so there's no need to iron.
WordNet 3.0 Sense Numbers: 2, 3, 4