Interferometric pulse

From Memory Alpha, the free Star Trek reference

An interferometric pulse is a type of energy emitted by the ships of the Swarm species, connecting all of them together in a lattice. The pulse is capable of neutralizing the deflector shields of a target vessel by assuming an opposing modulation. It also reflects the destructive energy of the target's directed energy weapons back towards it, rendering the target ship defenseless as the Swarm attacks.

In 2373, the Swarm nearly overwhelmed the USS Voyager thanks to their interferometric pulse. However, the crew was able to modify phasers to turn the interferometric pulse back on the attackers, causing a chain reaction that destroyed many of the Swarm ships. (VOY: "The Swarm")