You never stopped to think about it, did you?
Just a toy for your child, a plaything. Cheap, plastic, made overseas. Your toy shop carries many similar toys, sold in bargain bins by the hundreds, all of their myriad varieties. You can even impulse-buy one on your way out of the store. Suitable for the smallest youngsters; too large to be swallowed or a choking hazard, soft enough to offer no threat of injury. Rubber Duckies are a bath-time staple, have been for many decades.
But you never stopped to consider if “waterproof” means we can’t be drowned.
Inspired by this photo plus my sick mind. And Ernie, o’course.