Urza, Lord High Artificer + Corridor Monitor + Retraction Helix + Will, Scion of Peace

Urza, Lord High Artificer

Corridor Monitor

Retraction Helix

Will, Scion of Peace

How it works

1. Activate Will by tapping it.
2. Cast Retraction Helix by paying , targeting a creature you control that doesn't have summoning sickness.
3. Cast Corridor Monitor by paying due to Will.
4. When Corridor Monitor enters, it triggers, untapping the creature targeted by Retraction Helix.
5. Activate Urza's first ability by tapping Corridor Monitor, adding .
6. Activate the creature targeted by Retraction Helix by tapping it, returning Corridor Monitor from the battlefield to your hand.
7. Repeat from step 3.