Bound in Silence

Tribal Enchantment — Rebel Aura

Enchant creature
Enchanted creature can't attack or block.

2021-03-19:
Tribal is a card type (like creature or instant), not a supertype (like legendary). The type carries no rules that affect how it’s cast or how it behaves on the battlefield; it just allows the card to have creature types without being a creature.
2021-03-19:
If you put Bound in Silence onto the battlefield without casting it, perhaps using the “recruiting” ability of a card like Amrou Scout, it will enter attached to a creature. You choose that creature as you’re putting the Aura onto the battlefield. This doesn’t target that creature, so you could have it enter the battlefield attached to a creature an opponent controls with hexproof, for example. If there’s no creature on the battlefield it can be attached to, it stays in whatever zone it was in.
2021-03-19:
If Bound in Silence becomes attached to a creature that’s already attacking or blocking, the creature continues to attack or block as normal.