Requires

Wormfang Manta must be on the battlefield. Whisperwood Elemental must be on the battlefield. Shadow Guildmage must be on the battlefield. Shadow Guildmage does not have summoning sickness. Mana needed:

Steps

1. Tap Shadow Guildmage for to put Wormfang Manta on top of your library.
2. Wormfang Manta's LTB triggers, granting you an extra turn after this one.
3. At the beginning of your end step, Whisperwood Elemental triggers, manifesting Wormfang Manta.
4. Pay to turn it face up.
5. Repeat for infinite turns.

Results