Opening sentence choices:
Leroy knew there was a mermaid.
Bubbles rose to the surface.
The sheriff stared at the empty jail cell.
He tossed the shell into the air.
It was darker than expected.
It was a little late in the day to go fishing.
Brady put on his magic overalls.
And here's my Cajun-flavored story:
It was a little late in the day to go fishing, but gol durn if Rambles wasn't gonna go back out there and try again. He'd been fishing this lake for pert near thirty-seven years - through three marriages, fourteen children, two wars, and one death. One important death, anyway. He was the only soul what believed the legend of the Amblegator, a gator so big he done drunk up the Mississippi in one slurp, before a crawfish swung on his gullet and made him give it back.
Rambles was a born and bred Cajun and he loved the taste of smoked gator. He caught plenty of gator, sittin' on his porch over the muddy lake. He'd bait his hook with a live chicken or an armadillo or one of those neighbor kids if they didn't shut their traps. He caught plenty of big gators - eight, nine feet long with teeth the size of screwdrivers and a disposition like his first ex-wife. But they weren't the Amblegator. That was a life gator - one that made your whole life worthwhile. Nobody believed the tales, least of all his second wife. She was nice enough but they didn't see eye to eye on most things, like the number of beers a reasonable man should drink in a day, the importance of an education, or the utter dedication required for a lone man to catch one of the greatest beasts ever to walk this godforsaken earth.
But his third wife, Bessie, she understood. They were mad for each other like Cupid had got hisself drunk one day and shot them both full of too many arrows. Bessie'd sit out there on the porch with him and fish for the Amblegator too. She'd even talk trash about how she was gonna be the one to catch 'im, just to light the fire in Ol' Rambles' belly. But that Amblegator had swallowed her up, and now she lay at the bottom of that muddy lake, in that great beast's stinkin' belly. Rambles put another chicken on the hook.