Infantry Shield attached to a creature you control with power 7 or greater that does not have summoning sickness).
Notable Prerequisites
Hellkite Charger and the creature with
Infantry Shield attached cannot be blocked and killed by an opponent.
Steps
Declare the creature that has
Infantry Shield attached and
Hellkite Charger as attackers, triggering the creature and
Hellkite Charger.
Resolve the creature's trigger, creating a number of 1/1 Warrior creature tokens that are tapped and attacking equal to the creature's power.
Holding priority, activate
Phyrexian Altar seven times by sacrificing seven Warriors, adding ({5} magic symbol) ({R} magic symbol) ({R} magic symbol) .
Resolve the
Hellkite Charger trigger, causing you to pay ({5} magic symbol) ({R} magic symbol) ({R} magic symbol) to untap all attacking creatures you control and to get an additional combat phase after this one.
Repeat.
Notes
If
Hellkite Charger has power 7 or greater, you can attach
Infantry Shield to it. Just ensure to resolve the token creation ability first.