Sandsteppe Mastodon, Roaring Primadox, and Sage of Hours

Prerequisites

• Sandsteppe Mastodon in hand
• Roaring Primadox on the battlefield
• Sage of Hours on the battlefield
• Sage of Hours has the lowest toughness or is tied for the lowest toughness among creatures you control
• each turn available

Steps

1. Cast Sandsteppe Mastodon by paying
2. Sandsteppe Mastodon enters the battlefield, putting five +1/+1 counters on Sage of Hours
3. Activate Sage of Hours by removing all +1/+1 counters from it, causing you to take at least one extra turn after this one
4. Move to your next turn
5. At the begging of your upkeep, Roaring Primadox triggers, causing you to return Sandsteppe Mastodon from the battlefield to your hand
6. Repeat

Results

• Infinite turns