Here is a noteworthy Energy Weapon from World War Z
MTHEL, or Mobile Tactical High Energy Laser is a weaponized deuterium fluoride laser developed in a joint research project of Israel and the U.S. The size of a WWII-era searchlight, it is designed to shoot down aircraft and missiles from unfriendly nations. When used on soft targets, the heat of the laser produces a luminous and glowing array of fire as it burns the flesh off the bone. On high setting, it will vaporize the flesh right off a animal target, leaving a skeleton that shatters to dust a moment later, all of which takes roughly 2–3 seconds.
However, the MTHEL was found to be quite impractical. First is the massive expense. Second, they require a enormous source of power necessary - usually a convoy of HMMWVs (High Mobility Multi-Wheeled Vehicles) with generators, or mounted on the nose of a special retrofitted 747. Third, being deuterium fluoride based, it uses very highly toxic chemicals. And finally, it takes several seconds for the thing to cool down before acquiring new targets, while a skilled marksman can put down a dozen soft targets in the same amount of time. So unless one can get zombies to stand in a straight line, don't expect to win the zombie apocalypse with this oversized phaser.
It's made for a cultural milestone in the US's War. Fire of the Gods highlighted some of the weapons' more impressive features and marketed it as a new hope in the struggle against zombies, while leaving out the many disadvantages. It inspired countless survivors to continue fighting, and resist both suicide, and also the lesser understood Asymptomatic Demise Syndrome. Because, lets face it, watching a zombie get vaporized is pretty entertaining. As a zombie killer, it was a dud. However, the film helped save it for its original purpose during the Road to New York: clearing out minefields set by ignorant folk during the U.S. retreat. The mines did little good against zombies, and many which lay unmarked and untriggered posed a hazard for U.S. troops. Israel also used it for it's original purpose: defending their defensive zone from incoming missile and mortar fire in the Israeli Civil War.