Necrotic Ooze, Trench Behemoth, and Skyshroud Ranger

Prerequisites

• Necrotic Ooze on the battlefield
• Trench Behemoth in the graveyard
• Skyshroud Ranger in the graveyard
• You have at least one land card in hand
• Necrotic Ooze does not have summoning sickness

Steps

1. Activate Necrotic Ooze using Skyshroud Ranger's ability by tapping it, putting a land from your hand onto the battlefield
2. If the land is mana-producing and enters the battlefield untapped, you may activate it by tapping it, adding at least
3. Activate Necrotic Ooze using Trench Behemoth's ability by returning the land from the battlefield to your hand, untapping Necrotic Ooze
4. Repeat

Results

• Infinite landfall triggers
• Infinite mana lands you control that enter the battlefield untapped can produce