"Owl Eyes" (we never learn his real name) is one of the guests at Gatsby's parties. Nick and Jordan encounter him in Gatsby's huge show library, where he has just discovered that the volumes on the shelves have never had their pages cut. He assumes that most of the people at the party have been transported there by someone else:
“Who brought you?” he demanded. “Or did you just come? I was brought. Most people were brought.”
“I was brought by a woman named Roosevelt,” he continued. “Mrs. Claud Roosevelt. Do you know her? I met her somewhere last night. I’ve been drunk for about a week now, and I thought it might sober me up to sit in a library.”
This exchange highlights how haphazard Gatsby has been in collecting the crowds that he assumes he needs to demonstrate great wealth and thus his worthiness as a suitor for Daisy.
In the end, "Owl Eyes" proves himself morally superior to the rest of the accidental crowd when in Chapter 9 he is the only one of Gatsby's former guests to attend his funeral:
Owl-eyes spoke to me by the gate.
“I couldn’t get to the house,” he remarked.
“Neither could anybody else.”
“Go on!” He started. “Why, my God! they used to go there by the hundreds.” He took off his glasses and wiped them again, outside and in.
“The poor son-of-a-bitch,” he said.
As has been remarked several times, this is Gatsby's true epitaph, spoken by the proverbial "one honest man" in the anonymous mass.