Midnight Mass Explained

10. The Cats

One of the first mysteries viewers are introduced to is the appearance of hundreds of dead cats washed up on the beach after a storm. With their necks broken but without a drop of blood to be found anywhere, the discovery is a strange one.

Though the answer is never explicitly revealed, there's enough clues in place for viewers to solve this island-wide conundrum for themselves.

In the first episode, we learn that the Uppards are teeming with stray cats and that everything from that area gets washed down to that beach after storms. Likewise, we hear a lot of angry cats which Warren, Ooker, and Ali assume are either fighting or engaged in another physical act. However, neither are the case here.

Later, we see that the cats are being preyed upon by an unseen creature. This being the same winged creature which takes refuge in an abandoned building soon after.

Put all these pieces together and the cat killer is revealed to be the island's resident vampire. It spends its first night on the island feeding upon all the cats (that's why there's no blood), and the bodies are subsequently washed up during the storm.