Annie Dillard, in her book Pilgrim at Tinker Creek, writes:

At the end of the island I noticed a small green frog. He was exactly half in and half out of the water. He was a very small frog with wide, dull eyes. And just as I looked at him, he slowly crumpled and began to sag. The spirit vanished from his eyes as if snuffed. His skin emptied and drooped; his very skull seemed to collapse and settle like a kicked tent. ...

An oval shadow hung in the water behind the drained frog: then the shadow glided away. The frog skin bag started to sink.

I had read about the water bug, but never seen one. "Giant water bug" is really the name of the creature, which is an enormous, heavy-bodied brown beetle. It eats insects, tadpoles, fish, and frogs. Its grasping forelegs are mighty and hooked inward. It seizes a victim with these legs, hugs it tight, and paralyzes it with enzymes injected during a vicious bite. Through the puncture shoots the poison that dissolves the victim's muscles and bones and organs--all but the skin--and through it the giant water bug sucks out the victim's body, reduced to juice.

Hidden sins can suck the life out of us.