Doom's Time Platform, Rift Elemental, and Temporal Manipulation

Prerequisites

• Doom's Time Platform on the battlefield
• Rift Elemental in hand
• Temporal Manipulation in hand
• the first turn with each extra turn available

Steps

1. Cast Temporal Manipulation by paying its mana cost, causing you to take an extra turn after this one
2. Declare any creature as an attacker
3. When you do, Doom's Time Platform triggers, exiling Temporal Manipulation from your graveyard with two time counters on it
4. Move to your next turn
5. At the beginning of your upkeep, Temporal Manipulation's suspend ability triggers, removing a time counter from it
6. Activate Rift Elemental by paying and removing a time counter from Temporal Manipulation
7. Temporal Manipulation's suspend ability triggers, causing you to cast it without paying its mana cost
8. Resolve Temporal Manipulation, causing you to take an extra turn after this one
9. Repeat from step 2

Results

• Infinite turns
• Lock