Cast Doppelgang by paying ({15} magic symbol) ({G} magic symbol) ({U} magic symbol) , creating five token copies of Possessed Skaab and of the four mana-producing permanents.
When the Possessed Skaab tokens enter the battlefield, they trigger, returning Doppelgang and up to four other creature, instant or sorcery cards from your graveyard to your hand.
Activate seventeen of the mana-producing permanent tokens by tapping them, adding at least ({15} magic symbol) ({G} magic symbol) ({U} magic symbol) .
Repeat.
Once you have infinite tokens and mana, you may instead target any other permanents using Doppelgang.
Results
Infinite ETB.
Infinite storm count.
Infinite creature tokens.
Infinite magecraft triggers.
Infinite landfall triggers.
Infinite copies of any permanent on the battlefield.
Infinite mana permanents can produce.
Return all instant and sorcery cards from your graveyard to your hand.
Return all creature cards from your graveyard to your hand.