Activate Ashnod's Altar by sacrificing Pelakka Wurm, adding CC.
When Pelakka Wurm dies, its second ability and Nim Deathmantle trigger.
Resolve the Pelakka Wurm trigger, causing you to draw a card.
Resolve the Nim Deathmantle trigger from step 2, causing you to pay 4 to return Pelakka Wurm from your graveyard to the battlefield, and attach Nim Deathmantle to it.
When Pelakka Wurm enters the battlefield, its first ability triggers, causing you to gain 7 life.
Trudge Garden triggers, causing you to pay 2 to create two 4/4 Fungus Beast creature tokens.
Activate Ashnod's Altar twice by sacrificing the Fungus Beasts, adding CCCC.