There are permanents on the battlefield that enter the battlefield untapped and produce at least ({3} magic symbol) ({R} magic symbol) ({R} magic symbol) .
Cast Mythos of Illuna by paying ({2} magic symbol) ({U} magic symbol) ({U} magic symbol) , targeting anything but Skullwinder.
In response, cast Radiate by paying ({3} magic symbol) ({R} magic symbol) ({R} magic symbol) , creating copies of Mythos of Illuna that target each permanent besides the original target.
Resolve all copies of Mythos of Illuna, creating token copies of each permanent besides the original target.
The token copy of Skullwinder enters the battlefield, triggering itself, returning Radiate from your graveyard to your hand and allowing an opponent to return any card from their graveyard to their hand.
Activate the token lands or other mana-producing permanents created in step 3 by tapping them, adding at least ({3} magic symbol) ({R} magic symbol) ({R} magic symbol) .
Repeat from step 2, doubling the number of copies created in step 3 each repetition.
Results
An opponent returns all cards from their graveyard to their hand.
Infinite copies of all permanents.
Infinite magecraft triggers.
Infinite storm count.
Return all cards from your graveyard to your hand.