Catwoman Quicksand.

Taking a deep breath Catwoman's head goes below the surface. She knows it is vital that she holds on to her breath.
The Cat sinks deeper as the pressure increases it becomes more difficult to hold onto her breath as the pain in her chest becomes unbearable. No matter how much Catwoman tried she could not hold onto the last of the oxygen. With her eyes tightly closed the feline feels some bubbles pass over her face. She realizes they are the remaining oxygen in her lungs as the pain becomes intolerable...