Cast Thud by paying ({R} magic symbol) and sacrificing a creature you control with power seven or greater.
Holding priority, cast Reiterate with buyback by paying ({4} magic symbol) ({R} magic symbol) ({R} magic symbol) , creating a copy of Thud and returning Reiterate to your hand.
Resolve the Thud copy, causing you to create at least seven 3/1 Elemental Shaman creature tokens with haste due to Hostility.
Activate Thermopod seven times by sacrificing seven Elemental Shamans, adding seven ({R} magic symbol) .
Repeat from step 2 an arbitrarily large number of times.
Activate Thermopod's second ability by sacrificing Hostility, adding ({R} magic symbol) .
Hostility dies, shuffling itself into your library from your graveyard.
Cast Reiterate with buyback by paying ({4} magic symbol) ({R} magic symbol) ({R} magic symbol) , creating a copy of Thud and returning Reiterate to your hand.
Resolve the Thud copy, dealing at least seven damage to any target.