Har-bloody-har
It was sitting on the table in the corner of the rec room. Innocuously, like it had been there all along.
Susan was pretty sure she would have noticed something like that when she came in, but the island is...well, you can never be really sure of something like that. More disturbing than it's sudden, if rather lacking in fanfare, appearance was the fact it had a card attached bearing her name. It seemed to be some kind of enclosure, with a few coloured tubes running around it. Inside was a single grey rat.
Checking it carefully for a sign of anything out of the ordinary*, Susan took the small rat out of it's habitat and sat with it on a nearby chair. "I don't suppose there is a raven in a cage near by?" she asked aloud. The rat just sniffed her hand timidly, and refused to answer. Which was totally in character, for a rat.
It was cute, she had to admit that. Even if the little thing was an appallingly obvious joke on the part of the island.
"Har-bloody-har, Island."
*She wouldn't admit it, after all it was ludicrous to be checking for a tiny scythe, or making sure it didn't have glowing blue eyes. The rat obviously wasn't a skeleton. So far.