Activate Ashnod's Altar by sacrificing Ferrafor, adding CC.
When Ferrafor dies, Nim Deathmantle triggers, causing you to pay 4 to return Ferrafor from your graveyard to the battlefield and attach Nim Deathmantle to it.
When Ferrafor enters, it triggers, creating at least one creature token.
Activate Ashnod's Altar by sacrificing a creature token, adding CC.