If multiple attacking creatures must be blocked if able, the defending player must assign at least one blocker to each of them if possible. For example, if two such creatures were attacking and there were two potential blockers, they couldn't both be assigned to block the same attacker.
Goldenhide Ox
The constellation ability doesn't force any specific creature to block the target creature.
An Aura spell without bestow that has an illegal target when it tries to resolve won't resolve and will be put into its owner's graveyard. It won't enter the battlefield and constellation abilities won't trigger. An Aura spell with bestow won't be countered this way. It will revert to being an enchantment creature and resolve, entering the battlefield and triggering constellation abilities.
Magic: The Gathering · ™ & © Wizards of the Coast · Illus. Jack Wang
Card data via Scryfall. Rarix is fan-made; not endorsed by the rights holders.
