Activate Thermopod's second ability by sacrificing Phylath, adding ({R} magic symbol) .
Phylath dies, triggering Nim Deathmantle, causing you to pay ({4} magic symbol) to return Phylath from your graveyard to the battlefield, and attach Nim Deathmantle to it.
Phylath enters the battlefield, creating at least four 0/1 Plant creature tokens.
Activate Thermopod three times by sacrificing three Plants, adding ({R} magic symbol) ({R} magic symbol) ({R} magic symbol) .