Legality

Alchemy

Brawl

Commander

Duel

Gladiator

Historic

Legacy

Modern

Oathbreaker

Pauper

Pauper Commander

Penny

Pioneer

Standard

Timeless

Rulings
Mar 19, 2021

If the target permanent is an illegal target by the time Beast Within tries to resolve, the spell won't resolve. No player creates a Beast token. If the target is legal but not destroyed (most likely because it has indestructible), its controller does create a Beast token.

Jul 1, 2013

If the permanent is still a legal target but is not destroyed (perhaps because it regenerated or has indestructible), its controller still gets the Beast token.