Satoru Umezawa, Silver-Fur Master, and Great Whale

Prerequisites

• Satoru Umezawa on the battlefield
• Silver-Fur Master on the battlefield
• Great Whale in hand
• You control another nontoken creature that can attack this turn, and that cannot be blocked by an opponent
• You control up to seven lands that can tap to produce at least

Steps

1. Declare another nontoken creature as an attacker
2. When the creature isn't blocked by an opponent, activate up to seven lands you control by tapping them, adding at least
3. Activate Great Whale's ninjitsu ability by paying and returning the unblocked creature to your hand, putting Great Whale onto the battlefield tapped and attacking
4. Great Whale enters the battlefield, untapping the seven lands
5. Activate any creature card in your hand's ninjitsu ability by paying and returning Great Whale to your hand, putting the creature onto the battlefield tapped and attacking
6. Activate up to seven lands you control by tapping them, adding at least
7. Repeat from step 3

Results

• Infinite ETB
• Infinite LTB
• Infinite mana lands you control can produce
• Infinite untap of lands you control