Cast Sozin's Comet either from your hand by paying {3}{R}{R} or from exile for its foretell cost by paying {2}{R}.
Declare a creature as an attacker, triggering its firebending ability, adding {R}{R}{R}{R}{R}.
Move to your postcombat main phase. You will not lose the mana due to Electro.
Activate Aggravated Assault by paying {3}{R}{R}, causing you to untap all creatures you control and to get an additional combat and main phase after this one.
Repeat from step 2.

Infinite combat phases

Infinite red mana

Infinite untap of creatures you control

Infinite mana creatures you control can produce

Infinite damage to target player

Sozin's Comet

Aggravated Assault

Electro, Assaulting Battery

Declare a creature as an attacker, triggering Avatar Roku, adding six {R}.
Move to your postcombat main phase. You will not lose the mana due to Electro.
Activate Aggravated Assault by paying {3}{R}{R}, causing you to untap all creatures you control and to get an additional combat and main phase after this one.
Repeat.

Infinitely powerful red creatures you control until end of turn

Avatar Roku, Firebender

Declare Firebending Student as an attacker, triggering its ability, adding an amount of {R} equal to its power.
Move to your postcombat main phase. You will not lose the mana due to Electro.
Activate Aggravated Assault by paying {3}{R}{R}, causing you to untap all creatures you control and to get an additional combat and main phase after this one.
Repeat.

Firebending Student

Declare Zuko as an attacker, triggering its ability, adding an amount of {R} equal to the number of experience counters you have.
Move to your postcombat main phase. You will not lose the mana due to Electro.
Activate Aggravated Assault by paying {3}{R}{R}, causing you to untap all creatures you control and to get an additional combat and main phase after this one.
Repeat.

Zuko, Firebending Master

Declare Sun Warriors as an attacker, triggering its ability, adding an amount of {R} equal to the number of creatures you control.
Move to your postcombat main phase. You will not lose the mana due to Electro.
Activate Aggravated Assault by paying {3}{R}{R}, causing you to untap all creatures you control and to get an additional combat and main phase after this one.
Repeat.

Infinite ETB

Infinite creature tokens

Sun Warriors

Cast Searing Touch with buyback by paying {R}. Electro, Blood Funnel and Sedgemoor Witch trigger.
Resolve the Electro trigger, adding {R}.
Resolve the Sedgemoor Witch trigger, creating a 1/1 Pest creature token.
Resolve the Blood Funnel trigger, causing you to sacrifice the Pest.
When the Pest dies, it triggers, causing you to gain 1 life.
Resolve the Searing Touch spell.
Repeat.

Infinite LTB

Infinite sacrifice triggers

Infinite death triggers

Infinite damage

Infinite lifegain triggers

Infinite lifegain

Infinite storm count

Infinite magecraft triggers

Blood Funnel

Memory Crystal

Searing Touch

Sedgemoor Witch

Activate an animated land by tapping it, adding at least {U}.
Cast View from Above by paying {U}, targeting the animated land.
Orvar and Electro trigger.
Resolve the Electro trigger, adding {R}.
Resolve the Orvar trigger, creating a token copy of the animated land that is not a creature.
Resolve View from Above, returning it to your hand.
Activate the land token by tapping it, adding at least {U}.
Repeat from step 2.

Infinite landfall triggers

Infinite tapped Island tokens

Card That Animates a Land

Orvar, the All-Form

View from Above

Cast the noncreature permanent by paying {0}.
Activate The Tenth Doctor by paying at most {1}, removing three time counters from Reality Strobe.
Reality Strobe triggers, causing you to cast it from exile without paying its mana cost.
Electro triggers, adding {R}.
Resolve Reality Strobe, returning Mana Vault from the battlefield to your hand, and then exiling Reality Strobe with three time counters on it.
Repeat.

Noncreature permanent castable for {0}

The Tenth Doctor

Reality Strobe

Agatha of the Vile Cauldron

Cast Nameless Inversion from your graveyard, as it is a Knight card, by paying {1} due to Morophon.
Electro triggers, adding {R}.
Resolve Nameless Inversion, giving a creature -3/-3 until end of turn.
If the creature has toughness 0 or less, the creature dies as a state-based action.
Repeat as desired.

Reduce any number of target creatures' toughness to 0

Reduce the toughness of opponents' creatures to 0 when it enters the battlefield

Haakon, Stromgald Scourge

Morophon, the Boundless

Nameless Inversion

Combos with "Electro, Assaulting Battery"