Molten Echoes, Cordial Vampire, Phyrexian Altar, and Dusk Legion Sergeant

Prerequisites

• Molten Echoes on the battlefield
• Cordial Vampire on the battlefield
• Phyrexian Altar on the battlefield
• Dusk Legion Sergeant in hand
• available

Steps

1. Cast Dusk Legion Sergeant by paying
2. When Dusk Legion Sergeant enters, Molten Echoes triggers, creating a token copy of Dusk Legion Sergeant with haste
3. Activate the token Dusk Legion Sergeant by sacrificing it
4. When the Dusk Legion Sergeant token dies, Cordial Vampire triggers, putting a +1/+1 counter on each Vampire you control
5. Resolve the token Dusk Legion Sergeant's ability, giving nontoken Vampires you control persist until end of turn
6. Activate Phyrexian Altar by sacrificing another nontoken Vampire with base toughness 2 or higher, adding
7. When the Vampire dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it
8. When the Vampire enters, Molten Echoes triggers, creating a token copy of it with haste
9. Activate Phyrexian Altar by sacrificing Dusk Legion Sergeant, adding
10. When Dusk Legion Sergeant dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it
11. Repeat from step 2

Results

• Infinite LTB
• Infinite ETB
• Infinite colored mana
• Infinite sacrifice triggers
• Infinite death triggers
• Infinite creature tokens with haste
• Infinite +1/+1 counters on Vampires you control