Rules glossary
↑ Parent rule: 506.3 Only a creature can attack or block. Only a player, a planes…
506.3e 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.
No sub-rules.