Nightwing was a fantasy creature seen by Rand in his dreams.
Rand lives through a nightmare hallucination, as he falls victim to the power of the Invid Flower of Life. This dream seems real, and eventually provides Rand with an insight into the ultimate goals of the Invid. With his friends held Rand and the others defeat the monster Nightwing. (Robotech: The New Generation: 'Sandstorm)