What is "nullifiers"

Usage examples of "nullifiers".

Dreel knew they could not outdistance the Nullifiers, but those aboard the task force did not.

Not having enough experience to appreciate the effect of the Nullifiers, the fleet officers suddenly discovered that they could no longer see their quarry on the other side of the hole.

They were pretty honest about itthey told him of the Dreel, and the Zinder Nullifiers, and the widening hole in space.