Activate Ashnod's Altar by sacrificing Frost Fair Lure Fish, adding CC.
When Frost Fair Lure Fish dies, Nim Deathmantle triggers, causing you to pay 4 to return Frost Fair Lure Fish from your graveyard to the battlefield and attach Nim Deathmantle to it.
When Frost Fair Lure Fish enters, it triggers, creating two 1/1 Fish creature tokens and two tapped Treasure tokens.
Activate Ashnod's Altar by sacrificing a creature token, adding CC.