When Oliver is playing and he gets really excited, he starts to hiss.
But then, when he isn't feeling well, he will hiss.
He's the most bizarre cat. The other night he jumped into bed and ran up to Mr. Right while we were sleeping, and hissed directly at him. I knew right away this was one of those very occasional sick episodes and I immediately woke up, grabbed him, ran for the hallway.
Just in time for him to throw up Exorcist style at the top of the stairs.
Then he was fine.
Usually he just gets all wiggy and it doesn't involve throwing up. He has had about 6 episodes in his 3 1/2 year life so far.