Ric Flair," but he didn't know for sure. One of his fellow students was a big wrestling fan too, and he was sure! So when they left the cafeteria the other student let out a big holler for him (apparently one of Ric's trademarks). They asked their teacher about it later, and he confirmed that it was, indeed, the Nature Boy himself.
I checked online, and sure enough he had been hospitalized for something. I'm not sure what it was, and I hope he's okay, but I thought it was nice that Isaac got to see him up close and personal.