Spawn is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

How it works : Spawn

Original English text — Wizards of the Coast / Scryfall

No additional ruling has been published for this card.

Interactions with other cards

These cards' text mentions Spawn.

Glaring Fleshraker

Whenever you cast a colorless spell, create a 0/1 colorless Eldrazi Spawn creature token with "Sacrifice this token: Add {C}." Whenever another colorless creature you control enters, this creature deals 1 damage to each opponent.

Pawn of Ulamog

Whenever this creature or another nontoken creature you control dies, you may create a 0/1 colorless Eldrazi Spawn creature token. It has "Sacrifice this token: Add {C}."

Awakening Zone

At the beginning of your upkeep, you may create a 0/1 colorless Eldrazi Spawn creature token. It has "Sacrifice this token: Add {C}."

Kozilek's Command

Choose two — • Target player creates X 0/1 colorless Eldrazi Spawn creature tokens with "Sacrifice this token: Add {C}." • Target player scries X, then draws a card. • Exile target creature with mana value X or less. • Exile up to X target cards from graveyards.

Basking Broodscale

Devoid (This card has no color.) {1}{G}: Adapt 1. (If this creature has no +1/+1 counters on it, put a +1/+1 counter on it.) Whenever one or more +1/+1 counters are put on this creature, you may create a 0/1 colorless Eldrazi Spawn creature token with "Sacrifice this token: Add {C}."

Glimpse the Impossible

Exile the top three cards of your library. You may play those cards this turn. At the beginning of the next end step, if any of those cards remain exiled, put them into your graveyard, then create a 0/1 colorless Eldrazi Spawn creature token for each card put into your graveyard this way. Those tokens have "Sacrifice this token: Add {C}."

Emrakul's Messenger

Devoid (This card has no color.) Flying Whenever you draw your second card each turn, create a 0/1 colorless Eldrazi Spawn creature token with "Sacrifice this token: Add {C}."

Kozilek's Unsealing

Devoid (This card has no color.) Whenever you cast a creature spell with mana value 4, 5, or 6, create two 0/1 colorless Eldrazi Spawn creature tokens with "Sacrifice this token: Add {C}." Whenever you cast a creature spell with mana value 7 or greater, draw three cards.

Malevolent Rumble

Reveal the top four cards of your library. You may put a permanent card from among them into your hand. Put the rest into your graveyard. Create a 0/1 colorless Eldrazi Spawn creature token with "Sacrifice this token: Add {C}."

Spawning Pit

Sacrifice a creature: Put a charge counter on this artifact. {1}, Remove two charge counters from this artifact: Create a 2/2 colorless Spawn artifact creature token.

Chittering Dispatcher

Devoid (This card has no color.) Myriad When this creature leaves the battlefield, create a 0/1 colorless Eldrazi Spawn creature token with "Sacrifice this token: Add {C}."