Activate Aetheric Amplifier by paying {4} and tapping it, doubling the charge counters on Magistrate's Scepter
Activate Magistrate's Scepter's second ability by tapping it and removing three charge counters from it, causing you to take an extra turn after this one.
Repeat each turn.

Infinite turns

Aetheric Amplifier

Magistrate's Scepter

Activate Aetheric Amplifier by paying {4} and tapping it, doubling the loyalty counters on Teferi.
Activate Teferi's third loyalty ability by removing ten loyalty counters from it, causing you to take two extra turns after this one.
Move to your first extra turn.
Activate Teferi's first loyalty ability by putting a loyalty counter on it, causing you to loot.
Activate Aetheric Amplifier by paying {4} and tapping it, doubling the loyalty counters on Teferi.
Move to your second extra turn and repeat.

Teferi, Master of Time

If Karn has exactly one loyalty counter on it, activate its first loyalty ability by putting a loyalty counter on it.
Activate Krark-Clan Ironworks by sacrificing Ugin's Nexus. Ugin's Nexus will be exiled instead of being put into your graveyard due to its replacement effect, causing you to take an extra turn after this one.
Move to your next turn.
Activate Aetheric Amplifier by paying {4} and tapping it, doubling the number of counters on Karn.
Activate Karn's second loyalty ability by removing two loyalty counters from it, returning Ugin's Nexus from exile to your hand.
Cast Ugin's Nexus by paying {5}.
Repeat from step 2.

Combos with "Aetheric Amplifier"