Alright, this is the definitely the last of the "common objects in walls". We swear. Brace yourself, cat haters, because this one's a gem. See, a long, long time ago, around the 17th and 18th centuries, dried out cats were a real hit. People didn't have fidget spinners back then, so they had to make do with a desiccated feline to keep them amused. And the best place to put them was in their walls.
We're only half joking. Dried-out cats were put in walls, but not for fun. In fact, they were used as a way to ward off evil, we're guessing in a high-powered version of the toenails and urine in a bottle that we mentioned before. These were even more common than the bottle, in fact - apparently they're simply falling out of old walls all over England these days.