Atla Palani, Nest Tender, Mirror Entity, and Darksteel Colossus

Prerequisites

• Atla Palani, Nest Tender on the battlefield
• Mirror Entity on the battlefield
• Darksteel Colossus on the battlefield or in the library
• You have a way to increase only Atla Palani's toughness by at least one

Steps

1. Increase Atla's toughness by at least one
2. Activate Mirror Entity an arbitrarily large number of times by paying a total of
3. Resolve the first Mirror Entity ability, causing all creatures you control to have base power and toughness 0/0 and gain all creature types until end of turn
4. All creatures you control except Atla die as a state-based action due to having zero toughness
5. If Darksteel Colossus died this way, it shuffles itself into your library instead of being put into your graveyard
6. Atla triggers once for each creature that died
7. Resolve the first Atla trigger, revealing cards from the top of your library until you reveal a creature card, then putting the creature card onto the battlefield and all other revealed cards on the bottom of your library
8. Repeat step 7 for each remaining Atla trigger
9. Repeat from step 3 for each remaining Mirror Entity ability

Results

• Infinite death triggers
• Infinite ETB
• Infinite LTB