Nope. It happened when I had just one floor and the shark was just swimming in the air around me lol. He did this at least twice in my current game. I also can't seem to kill this shark at all, no matter how many times he comes to my raft normally and I attack with the spear. I think my shark in this game is just glitched; Immortal and has flying powers. I'll start a new game eventually and see if that one acts better.