Errantry | Magic: The Gathering
Formats Errantry is Legal in
Official Oracle Text for Errantry
Enchanted creature gets +3/+0 and can only attack alone.
—Arna Kennerüd, skyknight
Official Rulings for Errantry
10/1/2008 : If the enchanted creature attacks alone, then a spell or ability causes another creature to be put onto the battlefield attacking, that's fine.