Gathering of Darkness

Gathering of Darkness puts +1/+1 counters on an Army, and Great Ugly-Looking Goblin gives that counter-bearing Army menace, turning the amass body into a much harder threat to block.

After Fearsome Goblin Pair trades or is sacrificed, Gathering of Darkness returns it to hand while adding three counters to the Army created or enlarged by its death trigger. Recasting the Pair sets up another amass 4 when it dies again.

Goblin Plate Mail starts or enlarges the same Army that Gathering of Darkness amasses onto, then gives that concentrated counter-bearing threat +1/+0 and menace. Together they can quickly produce a large Army that is difficult to block profitably.

Casting Gathering of Darkness triggers Noisemaker to amass 1 before the spell itself amasses 3, producing four total Army counters while also returning a creature.

Amass 3 in one shot triggers The Great Goblin's counter payoff while rebuilding your hand.

Speak Secrets mills four cards to stock a creature for Gathering of Darkness to return; if Gathering itself is milled, Speak Secrets can instead put it back into your hand.

Gathering of Darkness creates or grows an Army that Tom, Bert, and William can sacrifice for a sizable draw, while its recursion half can recover a valuable nontoken creature previously sacrificed to the Trolls.

Gathering of Darkness supplies a 3-power Army that Bolg can sacrifice to deal 3 damage and potentially amass again from excess damage, while also returning another creature to provide future sacrifice material.

Gathering returns a creature card from your graveyard, which triggers Along the Crooked Way for an additional amass 1 on top of Gathering's amass 3.

Gathering of Darkness is a four-mana noncreature spell, so Uncover the Moon-Letters can turn casting it into drawing four cards and discarding two before Gathering resolves, adding substantial card selection to its recursion and amass value.

An Army equipped with Glamdring can use its power to reduce Gathering of Darkness's generic mana cost, and Gathering then adds three more counters to that Army, increasing Glamdring's cost reduction for subsequent instants and sorceries.

After Rhovanion Rampager dies and amasses based on its power, Gathering of Darkness returns it to hand while adding three more counters to the Army its death created or enlarged. Recasting the Rampager sets up another sacrifice and death-amass cycle.

Gathering of Darkness is a noncreature spell, so casting it pumps Gandalf for the turn and deals 1 damage to each opponent in addition to its recursion and amass effects.