2021-07-23 : If each creature the defending player controls can't block for any reason (such as being tapped), then the affected creature isn't blocked. If there's a cost associated with blocking the affected creature, the defending player isn't forced to pay that cost, so it doesn't have to be blocked in that case either.

2021-07-23 : Only one creature is required to block the affected creature. Other creatures may also block it and are free to block other creatures or not block at all.