Characters
If they ever try to trace any of those accounts, they're gonna end up chasing a figment of my imagination.
— Andy Dufresne · The Shawshank Redemption

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
The speaker predicts that an investigation into the accounts will lead pursuers toward something invented rather than something they can readily find. Calling the target a 'figment' turns the imagined pursuit into a joke. The confidence comes through without explaining exactly how the deception works.
Context reviewed