Ular.

A model had a pet snake. She loved her snake very much, the snake even had a special basket in her room for it to sleep in.

One day, the snake suddenly refused to eat.

So, the model brought the snake to see a vet.
"I even give my snake its favourite food, mice, but it still refuses to eat," explained the model.
The vet told her not to worry.

The model was unsatisfied, she brought the snake to the zoo, next.

After some inspection, the zoo keeper asked her, "Is there anything strange happening? Anything unusual with its behaviour?"

"No, no. Everything is fine, except the snake refuses to eat. The snake usually sleeps in its basket but a few nights ago, it began to sleep with me in my bed," the model said.

"I am afraid we have to kill your snake, miss," said the zoo keeper.

"What? Why?" the model was shocked to hear this.

"The reason your snake refuses to eat is because it wants to eat you. It sleeps with you in your bed because it was actually measuring its body against yours!"

So, the zoo keeper took her snake away.

The model was sad, obviously, so she bought a new snake to replace the old one.

True story, no joke.