Tangleclaw Werewolf
Creature — Werewolf Horror
This creature can block an additional creature each combat.
: Transform this creature.
"What has long, flesh-rending claws and enormous, bone-crushing teeth?" —Halana, Kessig ranger
Fibrous Entangler
Creature — Eldrazi Werewolf
Vigilance
This creature must be blocked if able.
This creature can block an additional creature each combat.
". . . because to be honest, I couldn't tell you." —Halana, Kessig ranger
Steven Belledin
Eldritch Moon (EMN)
• #174Rulings
The defending player, not you, chooses which creature blocks Fibrous Entangler.
(wotc • 2016-07-13)
Only one creature is required to block Fibrous Entangler. Other creatures may also block it, and are free to block other creatures or not block at all.
(wotc • 2016-07-13)
If Tangleclaw Werewolf transforms into Fibrous Entangler while it's attacking, having vigilance won't cause it to become untapped.
(wotc • 2016-07-13)
If each creature that could block Fibrous Entangler is tapped or is affected by a spell or ability that says it can't block, then none of them block. If there's a cost associated with having each of those creatures block, its controller isn't forced to pay the cost, so they don't have to block in that case either.
(wotc • 2016-07-13)
Rulings
The defending player, not you, chooses which creature blocks Fibrous Entangler.
(wotc • 2016-07-13)
Only one creature is required to block Fibrous Entangler. Other creatures may also block it, and are free to block other creatures or not block at all.
(wotc • 2016-07-13)
If Tangleclaw Werewolf transforms into Fibrous Entangler while it's attacking, having vigilance won't cause it to become untapped.
(wotc • 2016-07-13)
If each creature that could block Fibrous Entangler is tapped or is affected by a spell or ability that says it can't block, then none of them block. If there's a cost associated with having each of those creatures block, its controller isn't forced to pay the cost, so they don't have to block in that case either.
(wotc • 2016-07-13)