Dragged down by an Uruk?

[Eomer of the Rohirrim]

The notorious Water-Orcs were foes the likes of which Middle-earth had never seen before. Their speciality seemed to be in dragging Hobbits and small children into the water and then being killed by them. Unsurprisingly, the Water-Orcs did not last long. Sauron found them to be wholly unuseful. Mass unemployment followed and the Water-Orcs were reduced to living in caves picking fights with rats and badgers; fights they would usually lose.

They were thought to die out soon after the Fourth Age began. What Ainaserkewen speaks of was obviously a homage to the species by Peter Jackson, cut from the film because the audience wouldn't 'get it'.

The Water-Orc in the film was to be drowned by Frodo, after the Hobbit got him in a headlock and held him underwater for about 120 seconds. Alternative reports from deep within the movie-camp suggest that the scene was ditched because it was completely awful and boring.