When Dualcaster Mage enters the battlefield, it triggers, copying Black Sun's Twilight, optionally choosing to target a creature.
Holding priority, activate Thermopod's second ability by sacrificing Dualcaster Mage, adding ({R} magic symbol) .
Resolve the copy of Black Sun's Twilight, giving up to one creature -5/-5 until end of turn and returning Dualcaster Mage from your graveyard to the battlefield.
Repeat from step 3.
Results
Infinite LTB.
Infinite ETB.
Infinite sacrifice triggers.
Infinite death triggers.
Infinite red mana.
Infinite magecraft triggers.
Reduce any number of target creatures' toughness to zero.