If an effect puts a creature onto the battlefield attacking during the declare blockers step, combat damage step, or end of combat step, that creature enters the battlefield unblocked. See rule 508.4d.
April 14, 2023 · March of the Machine
If an effect would put a creature onto the battlefield blocking but the creature it would block isn’t attacking the entering creature’s controller, a planeswalker that player controls, or a battle that player protects, that creature does enter the battlefield, but it’s never considered to be a blocking creature.
May 3, 2019 · War of the Spark
If an effect would put a creature onto the battlefield blocking but the creature it would block isn’t attacking either the first creature’s controller or a planeswalker that player controls, that creature does enter the battlefield, but it’s never considered to be a blocking creature.
January 25, 2019 · Ravnica Allegiance
If an effect would put a creature onto the battlefield blocking but the creature it would block isn't attacking either the first creature's controller or a planeswalker that player controls, that creature does enter the battlefield, but it's never considered to be a blocking creature.
February 1, 2014 · Born of the Gods
If an effect would put a creature onto the battlefield blocking but the creature it would block isn’t attacking either the first creature’s controller or a planeswalker that player controls, that creature does enter the battlefield, but it’s never considered to be a blocking creature.
September 30, 2011 · Innistrad
If an effect would put a creature onto the battlefield blocking but the creature it would block isn't attacking either the first creature's controller or a planeswalker that player controls, that creature does enter the battlefield, but it's never considered to be a blocking creature.
June 17, 2011 · Commander 2011
If an effect would put a creature onto the battlefield blocking but the creature it would block
May 1, 2011 · New Phyrexia
If an effect would put a creature onto the battlefield blocking but the creature it would block isn't attacking either the first creature's controller or a planeswalker that player controls, that creature does enter the battlefield, but it's never considered to be a blocking creature.