Spider Spawning

Mana cost: {4}{G}
Type: Sorcery
Set: Innistrad Remastered #216 (uncommon)
Price: $0.31 USD

Create a 1/2 green Spider creature token with reach for each creature card in your graveyard.
Flashback {6}{B} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Spider Spawning has 10 printings, first in Innistrad (2011). EDHREC ranks it #8,071 among Commander cards. It appears most in Shelob, Child of Ungoliant decks (8,873 on EDHREC). 2 public decks on TCG run it. It has 7 official rulings.

Legality

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

Public decks that run Spider Spawning

Plunder the Graves - Commander 2015, led by Meren of Clan Nel Toth
Plunder the Graves - Commander Anthology, led by Meren of Clan Nel Toth

Commanders that run Spider Spawning most

Deck counts from EDHREC.

Often played with Spider Spawning

Cards that show up in the same decks on EDHREC.

Rulings

2011-09-22: The number of creature cards in your graveyard is counted when Spider Spawning resolves.
2021-03-19: You can cast a spell using flashback even if it was somehow put into your graveyard without having been cast.
2021-03-19: "Flashback [cost]" means "You may cast this card from your graveyard by paying [cost] rather than paying its mana cost" and "If the flashback cost was paid, exile this card instead of putting it anywhere else any time it would leave the stack."
2021-03-19: If a card with flashback is put into your graveyard during your turn, you can cast it if it's legal to do so before any other player can take any actions.
2021-03-19: A spell cast using flashback will always be exiled afterward, whether it resolves, is countered, or leaves the stack in some other way.
2021-03-19: You must still follow any timing restrictions and permissions, including those based on the card's type. For instance, you can cast a sorcery using flashback only when you could normally cast a sorcery.
2021-03-19: To determine the total cost of a spell, start with the mana cost or alternative cost (such as a flashback cost) you're paying, add any cost increases, then apply any cost reductions. The mana value of the spell is determined only by its mana cost, no matter what the total cost to cast the spell was.