You place a cell into a glass of distilled water. You come back five minutes later and the darn thing disappeared. What happened?
The cell was in a hypertonic environment and it took in too much water then exploded.
The cell was in an isotonic environment and it took a walk.

The cell was in a hypotonic environment and lost all its water.

The cell was in a hypotonic environment, took in too much water, and exploded.