If there's a cost associated with having a creature block the attacking creature, the defending player isn't forced to pay that cost, so it doesn't have to block in that case either
More than just depiction issues, however, six mana is also very steep for a simple ETB removal effect, even if the condition does guarantee that it can destroy almost any target
The reason is clear: scarcity combined with fandom intensity
The new keywords are Boast and Foretell
Like the flavor text says, The demons yoke is part leash, part noose. Yes it is
Turn it face up any time for its megamorph cost and put a +1/+1 counter on it.) Whenever a permanent you control is turned face up, you may return this card from your graveyard to the battlefield face up or face down