Effects that Alter a Creature's Power/Toughness (Anthem Effects)
Initial Card State
All permanents on the battlefield (
Eirdu as Isilu, Carrier of Twilight and
Jet without a -1/-1 counter on it).
Steps
Activate
Phyrexian Altar by sacrificing
Jet.
When
Jet dies, its persist ability and second ability trigger.
Resolve the second trigger, putting a +1/+1 counter on
Hex Parasite and another creature you control.
Resolve the persist trigger, returning
Jet from your graveyard to the battlefield with a -1/-1 counter on it.
When
Jet enters, its first and second ability triggers, dealing damage to a creature an opponent controls.
Activate
Phyrexian Altar by sacrificing
Hex Parasite, adding ({1} magic symbol) .
When
Hex Parasite dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
Activate
Hex Parasite by paying ({1} magic symbol) ({B} magic symbol) , removing the -1/-1 counter from
Jet.
Repeat.
Notes
The anthem must boost
Jet's toughness by 1 or more each iteration so it doesn't die due to having 0 toughness when it enters with a -1/-1 counter on it. You can also sacrifice another nontoken creature and use the second +1/+1 counter to counteract the -1/-1 counter on that creature. This loop can also be performed whenever an opponent controls a creature to destroy that creature.
Results
Lock.
Infinite LTB.
Infinite ETB.
Infinite colored mana.
Infinite sacrifice triggers.
Infinite death triggers.
Destroy all creatures opponents control.
Destroy each creature that enters the battlefield under an opponent's control.