Collin Harris, a technical artist who worked on the remake, shared a video on Twitter of a hoard of ducks being used to test the game's tech and effects. Ducks appear to explode from the table, and from the mists looms something rather more fowl...
Speaking to GamesRadar, Harris explained the duck model was created by his friend Alex, who was interning at Bluepoint Games. The model eventually made its way into the studio's asset library, and when Harris was looking for a model to carry out test demos, the duck's size and shape meant it fit the bill. He said that, It didn't hurt that it was also a funny juxtaposition to see a bright yellow rubber duck sitting in an incredibly detailed dark fantasy environment.
The devs obviously had fun with the ducks, with Harris explaining they multiplied and eventually morphed into the sort of monstrous giant duck you would expect to find in Dark Souls but the model had to be deleted to prevent it accidentally slipping into the final product.
Harris said, we used it for a bit as a placeholder mesh, but eventually it got to the point where there was a good amount of concern (for good reason) that due to the duck's internal popularity, that it would somehow find its way into the final game. So instead of taking the risk of potentially damaging our reputation with Sony, we chose the nuclear option. It was fun while it lasted, and will forever live on as one of my favorite game dev memories.