Balamb Garden // Command Beacon, Zuran Orb, Vigorous Farming and enough lands to cast Commander Lumra, Bellow of the Woods are on the battlefield. Opponent plays Lumra, sacrifices lands to Zuran Orb in response to Lumra trigger and then sacrifices Command Beacon to use its effect to put a commander from the command zone into their hand. The land, however, takes the Lumra from the battlefield, moves it to the command zone and then to their hand.

This allows them to infinitely loop Lumra and fetch all the lands from their deck and all other cards into their graveyard, since all lands enter untapped with Vigorous Farming.

Command Beacon should not take a commander from the battlefield, but only be able to change the commander's zone from command zone to hand if the commander is actually in the command zone.