Reaper

The Reaper is a multiplayer-only weapon introduced in the Hell Followed DLC. It's a gun that unleashes six-round bursts of Hell energy, and has a weapon modification that allows it to charge up a shot for increased damage. It was recovered directly from Hell, and unleashes tortured souls that annihilate opponents. It appears to be designed similar to the Unmaker from Doom 64.

The front end of the weapon has four claws which are normally spread apart, but can contract together to focus the weapon's energy when it is charged. The weapon features a vaguely insectile appearance, especially on its back end, which resembles an arthopod's cerci. The skull inside the weapon is covered by a thin transparent membrane, and its aura changes from blue to orange when the weapon is fired.

Tactical Analysis
The reaper has two firing modes. Its primary mode releases a quick burst of six compact plasma-like orbs of Hell energy and has a high rate of fire, with almost no recovery between bursts. The secondary mode allows the weapon to be charged up for a slower but more powerful attack. This secondary mode fires a laser-like stream of Hell energy which strongly resembles the attack of the Unmaker from Doom 64.

Doom Eternal
The weapon makes a surprise cameo during the second expansion for Doom Eternal, in The Ancient Gods - Part Two, where it's wielded by the new Demonic Trooper enemies. The weapon does not seem to share the same properties as its 2016 variant, as Troopers fire single projectiles at a moderate rate of fire, instead of six projectiles in burst-fire formation. They are also never seen making use of the weapon's secondary fire.