Emphasizing feelings:
* ...a ship caught in a sudden storm.
* ...a bird trapped in a cage.
* ...a mirror reflecting a distorted image.
* ...a melody played out of tune.
* ...a flickering candle in a darkened room.
Describing external factors:
* ...a child lost in a crowded market.
* ...a lone figure in a deserted landscape.
* ...a forgotten photograph in an old album.
* ...a whisper carried by a restless wind.
* ...a broken clock ticking with no purpose.
Adding a touch of mystery:
* ...a secret whispered in the dark.
* ...a ghost haunting a forgotten house.
* ...a dream you can't quite remember.
* ...a shadow lurking just beyond your sight.
* ...a puzzle with missing pieces.
The best way to finish the sentence will depend on the tone and meaning you want to convey.