You control a Warrior that does not have summoning sickness and that cannot be blocked and killed by an opponent.
Steps
Declare a Warrior you control as an attacker, triggering
Najeela, creating a 1/1 Warrior creature token that is tapped and attacking.
When the Warrior enters the battlefield,
Intruder Alarm triggers, untapping all creatures.
Holding priority, activate
Jegantha by tapping it, adding ({W} magic symbol) ({U} magic symbol) ({B} magic symbol) ({R} magic symbol) ({G} magic symbol) that cannot be spent to pay generic mana costs.
Activate
Najeela by paying ({W} magic symbol) ({U} magic symbol) ({B} magic symbol) ({R} magic symbol) ({G} magic symbol) , untapping all attacking creatures, giving them trample, lifelink and haste, and gaining an additional combat phase after this one.
Repeat each combat phase.
Results
Infinite ETB.
Infinite combat phases.
Infinite creature tokens with haste.
Infinite mana creatures you control can produce.
Infinite untap of creatures.
Infinite untap of creatures you control.
Metadata
In 210 decks according to EDHREC.
Bracket Tag
This combo has been estimated to be Exhibition (Bracket 1+).