Adrian Mellon is a minor character in IT. He is a young homosexual man in Derry, Maine and the life partner of Don Hagarty.
He grows fond of the town despite it's violent homophobic attitude and only agrees to leave because of Don. Before leaving, the two attend the town fair and on the way home, they are harassed by 3 homophobic teens, Webby Garton, Steven Bishoff Dubay and Chris Unwin. After the teens throw Adrian over a bridge, Pennywise drags him out of the water, bites into his armpit and cracks his ribs. Though Don and Chris witness this, nobody mentions Pennywise at the trial.
After Adrian's body was found, he was buried in the Derry Cemetery.