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