Goldfishing

Goldfishing (or playing against a goldfish) is the practice of playing without an opponent as in drawing a starting hand and proceeding to continue to play until an opponent who does nothing to stop you from accomplishing the gameplan is defeated. While this is usually useless for reactive decks, it can give some insight into the speed of aggro or combo decks as well as help players unfamiliar with the deck to understand the basic principles of how to play it. It can also be used to subjectively judge a mana base, as in how likely is it to sufficient mana of all colors required to play certain spells.

Occasionally, real players who are defeated without having had any real impact on the game are also derisively called "Goldfish".