Phyrexian Altar + Wormfang Drake + Sun Titan

Phyrexian Altar

Wormfang Drake

Sun Titan

How it works

1. Cast Wormfang Drake by paying its mana cost.
2. When Wormfang Drake enters, its first ability triggers, exiling Sun Titan.
3. Activate Phyrexian Altar by sacrificing Wormfang Drake.
4. When Wormfang Drake dies, its second ability triggers, returning Sun Titan from exile to the battlefield.
5. When Sun Titan enters, it triggers, returning Wormfang Drake from your graveyard to the battlefield.
6. When Wormfang Drake enters, its first ability triggers, exiling Sun Titan.
7. Repeat from step 3.