Human grenades are generally simple affairs - explosive charges activated either by manual activation, proximity detection, or on precisely set timers to batter targets with shrapnel, flaming defoliant or an electromagnetic pulse, or confuse them with searing light and deafening thunder. Covenant systems, on the other hand, use a far more inefficient and complex method - the Type-1 Antipersonnel Grenade, known colloquially as the Plasma Grenade, flash-heats gases contained within the grenade, producing an extremely rapid explosion of superheated plasma, emiting a burst of radiation and electromagnetic energy in its wake. Such devices are devastating in their effects on human equipment - plasma grenades can be used as demolitions charges, melting through battleplate, irradiate the targets that aren't killed by the initial blast, and are able to differentiate between "smart" and "dumb" targets - background scenery versus enemy units and equipment."
Like most Covenant technology, the Plasma Grenade is derived from Forerunner technology that even its makers had little understanding of. At its most basic, the grenade is a small electromagnetic field generator and superheater linked to a short timer. Once activated, the grenade superheats gases stored internally or taken from external sources - this plasma is contained and compressed by a powerful EM field for the duration of its timer, usually lasting approximately three seconds, and once this period expires the EM field dissipates, allowing the plasma to escape with explosive force. The electromagnetic field produced by the grenade is damaging enough, and has been used by special operations forces to cripple both human and Covenant electronics, and interfering with the operation of weapons, vehicles and equipment. The plasma explosion is also destructive in its own right, capable of blasting through several centimeters of standard UNSC battleplate. The most devastating property the Plasma Grenade possesses, however, is its unusual adherence properties - the grenades are capable of differentiating enemy personnel and equipment from background scenery. Plasma grenades will usually bounce off of items such as doors or walls, while adhering to even unoccupied vehicles. Even after study by TEMERITY personnel, the exact mechanics remain vague, though are speculated to be electromagnetic in origin.
This adherence also allows it to be used by special operations forces as the Covenant equivalent of UNSC shaped charges, used for breaching internal doorways during clearing operations by specops forces. Plasma grenades are also standard issue for Unggoy "Grunt" squads, both in an anti-personnel role and as makeshift explosives in suicidal charges. Such "suicide squads" as they have come to be known have proven devastating against unalert UNSC forces, enabled by the disabling of the timer function, allowing Suicide Grunts to charge over extended periods of time without the grenades explosing in their hands. Such tactics have also proved unneccessarily wasteful of Grunt lives - carrying two grenades in a suicide attack leaves them vulnerable, open to accurate fire, though even after death they remain a threat as the grenades detonate.
Popular legend holds that plasma grenades, like many of the Covenant's other plasma-based weaponry, possessed radioactive properties pose health risks for UNSC personnel. Such rumours have been detrimental to ONI efforts to recover salvagable materials for study, and seem to be largely unfounded. Borens Syndrone has often been blamed on Covenant plasma grenades, though it is more likely that affected individuals contracted the condition from long-term prolonged exposure to UNSC nuclear ordnance, rather than short-term exposure to a plasma grenade. Usually the effects of Covenant ordnance are immediately lethal, giving little chance to study observable long-term effects.
- "I wouldn't touch one if my life depended on it. I heard it can make you sterile!"
- "You see a blue glow on the edge of your vision, and you instinctively duck. These things are nasty - why can't the Covenant just stick to frags and flash-bangs like everybody else?!"
- "Demon Flare! SCATTER!!!"
- "Who the hell makes these things? They just turn up everywhere, in weapons crates - are there factories, or do they get handmade?"