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 a 4/4 Fungus Beast and a 1/1 Squirrel creature token.
Activate Ashnod's Altar twice by sacrificing the Fungus Beast and Squirrel, adding CCCC.
Repeat.
This intricate loop transforms a single giant wurm into a self-sustaining engine of life and bone, starting when Ashnod's Altar converts Pelakka Wurm into the mana needed to fuel Nim Deathmantle's resurrection trigger. Every time the Wurm enters the battlefield, its massive life-gain triggers Trudge Garden, which not only yields a 4/4 Fungus Beast token but also invites Chatterfang, Squirrel General's replacement effect to flood the board with extra Squirrels. You then feed those generated tokens right back into Ashnod's Altar, generating a net surplus of mana and drawing your entire deck thanks to the Wurm's own dying breath.