Anti-Enerjak Weapon

The Anti-Enerjak Weapon was a powerful piece of weaponry crafted by the Brotherhood of Guardians shortly after Enerjak's last appearance, preparing for the possibility of his return (believing a being that powerful should not be allowed to exist after seeing what he was capable of), and was designed to destroy him if he ever returned. It it appeared as a silver rod with a arched top, and it's assumed to be an energy-based weapon (due to Enerjak's nature as a Chaos Demi-God), and was described as being "a perfectly humane way" to kill him and his host. It was personally crafted by Locke and Sabre while safely ensconed in Haven.

Creation
After Enerjak's return from space and rampage on Echidnaopolis, the Brotherhood of Guardians decided it was necessary to develop a weapon capable of killing him should he return once again. Thus, Locke and Sabre created the Anti-Enerjak Weapon. Not long before the Eggman Empire invasion of Angel Island, The weapon was hidden in the ruins of the Grand Conservatory, with Archimedes, hiding in the underground city, keeping it safe. (StH: #183)

Role during Enerjak's Rebirth
As part of his plan to use Enerjak to destroy all life on Mobius, Dr. Finitevus hired and sent the Destructix to guard and keep watch over the weapon, and to prevent anyone from using it on Enerjak (though un-willingly, as Scourge the Hedgehog first voiced the idea of smashing it in the first place). Locke, believing that Knuckles, his son, no longer existed and he was only Enerjak and it was the only option they had left, elected to use the device on him. But due to his inability to access the Master Emerald due to The Hex placed upon it, was left weakened and unable to secure it without the Emerald's aid. To this end, Locke, needing extra muscle, used his Warp Ring to bring Sonic the Hedgehog and Julie-Su to the Island, and asked them for help. Initially they believed the gizmo was designed to restore Enerjak's host to normal, only for Locke to correct Sonic by saying that his forefathers and he had crafted a weapon, and they must help him destroy Enerjak. (StH: #182, #183)

While Julie-Su was outraged and argued with Locke about destroying Knuckles, Sonic also refused to aid in the destruction of his friend, though kept his doubts to himself, instead planning to break the effects of the Hex with the positive aura he gave off as Super Sonic (similar to what happened to Perfect Chaos). Sonic pretended to agree, and were able to get to the Conservatory with Archimedes' aid, and Sonic found the weapon. Just when it seemed they would be confronted again by the Destructix, Sonic promptly smashed the weapon with a Sonic Spin attack. (StH: #183)

Because Doctor Finitevus only paid the Destructix to keep watch over the weapon, Sleuth Dog believed they were done on the Island and ordered the others to leave the battle, and they then retreated through Warp Rings. Meanwhile, Sonic's plan failed, and instead were forced to break the Hex by sacrificing one of their own, Locke, guilt-ridden and determined to make amends for all he had put his son through, performing the ceremony and dying as a result. (StH: #184)

Background Information

 * In an interview, writer Ian Flynn described that the weapon worked liked a Chaos Syphon, but would then destabilize the energy it absorbed and release it at a target (which supplied the energy in the first place) which would then cause an entropic feedback in the target, ultimately destroying/killing it.