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.
Repeat.
This loop turns the cycle of life and death into a self-sustaining engine by using Ashnod's Altar to sacrifice Pelakka Wurm, which generates the exact mana needed to fuel Nim Deathmantle's resurrection trigger. Every time the Wurm returns, it gains you 7 life to feed into Trudge Garden, and Parallel Lives steps in to double your resulting 4/4 Fungus Beast tokens. Those extra tokens are then fed right back into the Altar for even more mana, letting you convert your death and lifegain triggers into an endless cascade of card draw and board presence.