The Borg were the most fearsome foe in Star Trek history, and their appearances in Star Trek: The Next Generation were often the best episodes of the series. First appearing during the second season of TNG, the cybernetic organisms eventually resurfaced in the Alpha Quadrant and wreaked havoc on Starfleet's armada. Designed only for assimilating all life in the galaxy, the Borg's unquenchable thirst for universal domination made them impossible to reason with, and their vast array of technology made them nearly unstoppable. Though they only appeared a few times in TNG, they always left their mark on the crew of the Enterprise-D.
Used surprisingly sparingly throughout TNG's seven seasons, the creators of the series were clever enough not to overuse their heart-stopping villains, and that made each Borg episode unique. Though Picard's Enterprise beat the Borg in nearly every encounter, it usually required an unusual amount of creative thinking and ingenuity. Most frighteningly of all, the Borg returned each time stronger than the last, and they became more difficult to vex as a result. Besides being the galaxy's biggest villains, the Borg episodes also often explored deeper moral issues that gave Picard and company internal struggles to grapple with as well as external ones.
