Herald of Anguish

Mana cost: {5}{B}{B}
Type: Creature — Demon
Power / toughness: 5 / 5
Set: Aether Revolt #64 (mythic)
Price: $0.69 USD

Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)
Flying
At the beginning of your end step, each opponent discards a card.
{1}{B}, Sacrifice an artifact: Target creature gets -2/-2 until end of turn.

Herald of Anguish has 4 printings, first in Aether Revolt (2017). EDHREC ranks it #11,671 among Commander cards. It appears most in Mishra, Eminent One decks (917 on EDHREC). 1 public deck on TCG runs it. It has 8 official rulings.

Legality

commander: legal
legacy: legal
vintage: legal
pauper: not legal
modern: legal
pioneer: legal
standard: not legal
brawl: legal

Public decks that run Herald of Anguish

Mishra's Burnished Banner - The Brothers' War Commander, led by Mishra, Eminent One

Commanders that run Herald of Anguish most

Deck counts from EDHREC.

Often played with Herald of Anguish

Cards that show up in the same decks on EDHREC.

Rulings

2017-02-09: Equipment attached to a creature doesn't become tapped when that creature becomes tapped, and tapping that Equipment doesn't cause the creature to become tapped.
2017-02-09: Tapping an artifact won't cause its abilities to stop applying unless those abilities say so.
2017-02-09: If an artifact you control has a mana ability with {T} in the cost, activating that ability while casting a spell with improvise will result in the artifact being tapped when you pay the spell's costs. You won't be able to tap it again for improvise. Similarly, if you sacrifice an artifact to activate a mana ability while casting a spell with improvise, that artifact won't be on the battlefield when you pay the spell's costs, so you won't be able to tap it for improvise.
2017-02-09: When calculating a spell's total cost, include any alternative costs, additional costs, or anything else that increases or reduces the cost to cast the spell. Improvise applies after the total cost is calculated.
2017-02-09: Improvise can't pay for {W}, {U}, {B}, {R}, {G}, or {C} mana symbols in a spell's total cost.
2017-02-09: Improvise can't be used to pay for anything other than the cost of casting the spell. For example, it can't be used during the resolution of an ability that says “Counter target spell unless its controller pays {3}.”
2017-02-09: Improvise doesn't change a spell's mana cost or mana value.
2017-02-09: Because improvise isn't an alternative cost, it can be used in conjunction with alternative costs.