Molecular reversion field
The Fermi caught in a molecular reversion field
Diagram of a molecular reversion field
A molecular reversion field was a spatial anomaly that could interfere with transporter patterns and the molecular structures of objects passing through it.
In 2369, the shuttlecraft Fermi was trapped in and destroyed by such a field. Traveling aboard the shuttle were Captain Jean-Luc Picard, Ensign Ro Laren, Keiko O'Brien, and Guinan. As the shuttle began to break up, the USS Enterprise-D attempted to beam them off the shuttle. The molecular reversion field obscured portions of their patterns, in particular the rybo-viroxic-nucleic structure of their DNA, and the transporter re-materialized all four of them without it, causing them to materialize as physically twelve-year-olds. (TNG: "Rascals")