Elemental Mastery, Captain of the Mists, and Conspiracy

Prerequisites

• Elemental Mastery on the battlefield
• Captain of the Mists on the battlefield
• Conspiracy on the battlefield
• Elemental Mastery attached to Captain of the Mists
• Captain of the Mists does not have summoning sickness
• "Human" chosen with Conspiracy

Steps

1. Activate Captain of the Mists by tapping it, creating at least two 1/1 Elemental creature tokens with haste
2. When the Elementals enter the battlefield as Humans due to Conspiracy, Captain of the Mists triggers, untapping itself
3. Repeat

Results

• Infinite creature tokens with haste
• Infinite ETB