Dredge

Dredge is the mechanic attributed to the Golgari in the Ravnica Block. It is a mechanic of recursive nature, where the owner of a card in a graveyard with said ability can return the card to their hand by choosing to skip his or her draw and put a number of cards from his or her library into his or her graveyard. The actual number of cards that must be put into a graveyard is written on each card with Dredge. Dredge only appears on green and/or black cards.

From the Comprehensive Rules:

• 502.47. Dredge
  • 502.47a Dredge is a static ability that functions only while the card with dredge is in a player's graveyard. "Dredge N" means "As long as you have at least N cards in your library, if you would draw a card, you may instead put N cards from the top of your library into your graveyard and return this card from your graveyard to your hand."
  • 502.47b A player with fewer cards in his or her library than the number required by a dredge ability can't put any of them into his or her graveyard this way.

One of the most popular uses of Dredge is to use it to quickly fill your graveyard. A famous deck based on Ichorid originated from this concept. Such decks work best with cards with high Dredge numbers, such as Golgari Grave-Troll and Stinkweed Imp. Another style of decks using this mechanic that debuted in the tournament scene are Life from the Loam decks, which use the card to gain card advantage by continuously recycling lands with cycling, as well as other utility lands like Wasteland and Cephalid Coliseum.