There's also the infamous video of (well-known professional player) Luis Scott-Vargas "breaking" MTGO by causing the game to wind up in a non-terminating loop o

There's also the infamous video of (well-known professional player) Luis Scott-Vargas "breaking" MTGO by causing the game to wind up in a non-terminating loop of mandatory actions: https://www.youtube.com/watch?v=AGXG5rNe_tI https://www.youtube.com/watch?v=AGXG5rNe_tI For those who are confused, the card involved there is Oblivion Ring: http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=397760 http://gatherer.wizards.com/Pages/Card/Details.aspx?multiver... Its effect is that, when it comes into play, you choose a non-land card in play that gets exiled (removed from play) for as long as Oblivion Ring stays in play, then gets returned once Oblivion Ring leaves play. This game devolves into a situation where there are three Oblivion Rings and no other non-land cards, so: Ring 1 exiles Ring 2, which returns Ring 3, which exiles Ring 1, which returns Ring 2, which exiles Ring 3, which returns Ring 1, which exiles Ring 2, and so on to infinity. The rules state that when a loop like this occurs (which is not often in real play), the game is an automatic draw.