Warp 11

Contact with a truly alien spacebound species of energy beings leads to a startling discovery as they lodge themselves in the Enterprise's nacelles and act as a kind of symbiont with the warp coils, increasing the ship's drive to warp 11 capacity. After a few parsecs travel, the creatures disengaged and continued on their separate way. Their kind has never been found by the Federation, since.

Reimagined Enterprise by Madkoifish.