Activate Ashnod's Altar by sacrificing a creature token, adding ({C} magic symbol) ({C} magic symbol) .
Mirkwood Bats triggers, causing each opponent to lose 1 life.
Bloodthirsty Conqueror triggers for each opponent.
Resolve the first trigger, causing you to gain 1 life.
Trudge Garden triggers, causing you to pay ({2} magic symbol) to create a 4/4 Fungus Beast creature token.
Mirkwood Bats triggers, causing each opponent to lose 1 life.
Bloodthirsty Conqueror triggers for each opponent.
Holding priority, repeat from step 1.
Resolve all remaining Bloodthirsty Conqueror triggers, causing you to gain that much life, choosing not to pay for the Trudge Garden triggers in between.