You control at least one additional creature with power two or greater.
You have not cast an instant or sorcery this turn.
You control at least one Rogue that cannot be blocked by an opponent and that does not have summoning sickness.
({5} magic symbol) ({U} magic symbol) on the first turn, with at most ({3} magic symbol) ({U} magic symbol) available each odd-numbered extra turn and ({5} magic symbol) ({U} magic symbol) each even-numbered extra turn available.
Steps
Deal combat damage to an opponent using a Rogue.
Cast Notorious Throng for its prowl cost by paying ({5} magic symbol) ({U} magic symbol) and sacrificing a creaature with power two or greater, targeting yourself.
Notorious Throng's casualty ability and Talrand trigger.
Resolve the Notorious Throng trigger, copying it, targeting yourself.
Resolve the Talrand trigger, creating a 2/2 Drake creature token.
Resolve both Notorious Throngs, causing you to take two extra turns after this one.
Move to your first extra turn.
Cast Call to Mind by paying ({2} magic symbol) ({U} magic symbol) and sacrificing a Drake, targeting Mystic Retrieval.
Call to Mind's casualty ability and Talrand trigger.
Resolve the Call to Mind trigger, copying it, targeting Notorious Throng.
Resolve the Talrand trigger, creating a 2/2 Drake creature token.
Resolve both Call to Minds, returning Notorious Throng and Mystic Retrieval from your graveyard to your hand.
Move to your second extra turn.
Repeat steps 1 through 7 one additional time.
Cast Mystic Retrieval by paying ({3} magic symbol) ({U} magic symbol) and sacrificing a Drake, targeting Call to Mind.
Mystic Retrieval's casualty ability and Talrand trigger.
Resolve the Mystic Retrieval trigger, copying it, targeting Notorious Throng.
Resolve the Talrand trigger, creating a 2/2 Drake creature token.
Resolve both Mystic Retrievals, returning Notorious Throng and Call to Mind from your graveyard to your hand.
Move to your second extra turn.
Repeat.
Results
Infinite turns.
2 Instant/Sorcery with "Return Instant/Sorcery from GY to hand".