Animals, and indeed people, look very different when they have decomposed even slightly. Unless you are a biologist with training YOU WILL NOT BE ABLE TO IDENTIFY AN ANIMAL’S SKULL or even a decomposed body with a bit of skull poking through. God, I’m not any kind of biologist but I at least know where I’m ignorant.

Clearly this is an example taken to the extreme, in which a normal animal is mistaken for a monster because people don’t know that ordinary animals can have rather terrifying and outlandish looking skulls/decomposed states.