Scupper usually means an unexpected action or event ruins a plan.

Unexpected Obstacles

Scupper often carries a negative feel, as it implies failure or destruction.

Negative Connotation

Scupper implies the plan was going well until it was suddenly stopped.

Scuppers are part of a ship's design, meant to drain water.

Scuppers help ensure the ship's safety by preventing water accumulation.

Scuppers are particularly important during bad weather or high seas.

 Bingo. I started seeing these fish scupper underneath that cave. I took my shot. And I got it.