The title of this article is conjectural.
Although this article is based on official information, the actual name of this subject is pure conjecture.
This article is about the weapon cut from Episode One. For the weapon cut from Half-Life 2, see Hopwire Grenade.
The Vortex Hopwire (also known as Black Hole Grenade) is an unfinished and highly unstable weapon cut from Half-Life 2: Episode One. Its proper name is unknown, as the HUD only gives "#HL2_Hopwire". It is also unknown how it was originally to fit into the storyline, although it was probably to be used against Striders (being an equivalent of their warp cannon, only more powerful), as suggested by the console commands "hopwire_strider_hits" and "hopwire_strider_kill_dist".
It is only obtainable through the use of the console, with the commands "hopwire_vortex 1", then "give weapon_hopwire". In maps where several Hopwires can be spawned, the crosshair must be located on it to activate it, otherwise it will spawn a second Hopwire. It creates a small black hole (deforming the view as at the start of a Strider fire) that sucks in and disintegrates almost everything next to it, including the player. When held by the player, it appears as the standard grenade, and a Rollermine when thrown.
For some reason, it will only be given to the player once per playthrough, once per saved file or once per chapter. Its maximum ammo also varies from a map to another, from 1 to 3. When used on Rebels/Citizens, it does not always kill them but spawns ragdolls of them instead, while they remain alive and try to run away from the black hole (this also applies to Barney or Alyx, although in her case she dies regardless). Killing Alyx with it does not always end the game. It randomly crashes the game in most of the situations. Although it has the same entity, it is unrelated to the Hopwire Grenade cut from Half-Life 2. The Black Hole Gun, originally designed for Quiver, was probably to produce similar effects.