Black Hole Gauntlet

Stats

Values as the League of Legends Wiki's item data lists them, for every mode; the data doesn't state their units.

Effects

• Dark Star (unique): Summon a black hole at the target location after a 0.5-second delay that lasts for 2 (+ 0.1 per 100 bonus health) seconds. Enemies within are dealt 30 to 100 (+ 5% of user's maximum health) magic damage every second, slow by 30%, and kinematics inward until they reach the horizon at the center. Additionally, for each enemy champion inside the black hole, generate 1 stack of Accretion per second.
• Accretion (unique): Basic attacks on-hit and immobilize effects against enemy champions generate 1 and 5 stacks of Accretion, respectively, up to 50. For each Accretion stack, gain 10% base health regeneration, up to 500% base health regeneration at maximum stacks. Additionally, for every 10 Accretion stacks, gain 20% increased size, up to 100% at maximum stacks. Stacks are reset every round and between each phase in a round.³

• Black Hole Gauntlet is included in a Cho'Gath build with Stackosaurus Rex, Tank Engine, Heavy Hitter, Guilty Pleasure, and Clothesline, alongside Heartsteel, Lightning Rod, Cloak of Starry Night, Demon King's Crown, and Overlord's Bloodmail.⁵
• Black Hole Gauntlet and Apex Inventor are recommended prismatic item and augment options for Maokai.⁶
• Black Hole Gauntlet is one of the main damage sources on tank Warwick, alongside Sunfire and Bloodmail. That build needs a teammate who can peel or deal burst damage to win.⁷
• Pair Black Hole with a lot of health on a tank.⁸
• Pair Black Hole Gauntlet with Apex Inventor and a 20k-health tank to have three large black holes down at once.⁹

Dark Star's black hole has a smaller horizon at its center that also increases in size with the black hole's radius; the horizon acts as impassable terrain.¹⁰ Patch unknown

Dark Star's black hole radius increases in increments of 10 units and cannot be modified during its lifetime.¹¹ Patch unknown

• Black Hole Gauntlet alongside Heartsteel and Tank Engine made one champion immovably gigantic.¹²

Since patch 26.10, black hole size scales more directly with champion size.¹³

In the eight-teams-of-two format, Phantom Hammer's on-hit shots triggered Black Hole Gauntlet's Accretion stacks.¹⁴³ Earlier Arena format

Earlier formats

Black Hole Gauntlet could trigger Ethereal Weapon for the Grub and bees; after being hit once, they slowly dealt damage over time.¹⁷ 8x2 duos

• Black Hole Gauntlet works well with a 16-second black hole duration.¹⁸ 8x2 duos
• Black Hole Gauntlet is a strong prismatic item for carrying through weak early rounds in an Anvil build.¹⁹ 8x2 duos

A Kog'Maw became untargetable and took no damage from Black Hole Gauntlet.²⁰ 8x2 duos