In the book, Mellon was a free lance writer from Portland, in Derry on assignment to write about the canal when he met Don Hagarty, and chose not to leave. He had been casually working on a novel "since his third year of college, and that had been twelve years ago." He grew fond of the town despite its 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 three homophobic teens, Webby Garton, Steven Bishoff Dubay and Chris Unwin. However, Mellon fights back, making cheeky comments. Just before a fight is about to break out, the teens are stopped by a police officer, who tells Mellon and Hagarty to leave before things get worse. The teens later confront Mellon and Hagarty at The Kissing Bridge and brutally physically assault the two men, particularly Mellon not allowing him his aspirator. After the teens throw Mellon over the bridge, Pennywise drags him out of the water, bites into his armpit and cracks his ribs and bites in "like he was going for his heart." Though Don and Chris witness this and tell the police. One officer mentions this to the ADA, who hotly dismisses this. At the court trial, nobody mentions Pennywise. After Mellon’s body was found, he was buried in the Derry Cemetery.
Mellon does not appear in the 1990 miniseries nor is he mentioned or referenced in any way.
It: Chapter Two
- "I don't, but Meg Ryan called. She wants her wig back."
- ―Mellon to Webby
Pennywise later uses Adrian as a form in order to taunt Richie briefly, presenting Richie with a flyer for his own funeral.
- Mellon’s death is inspired by the murder of Charlie Howard in Bangor, Maine in 1984.