Venser, Corpse Puppet + Tainted Observer + Ashnod's Altar

Prerequisites

• You have a way to cause a creature to enter the battlefield under your control.

Steps

1. 1Cause a creature to enter the battlefield under your control.
2. 2Tainted Observer triggers, causing you to pay to proliferate.
3. 3Venser triggers, creating a legendary 3/3 The Hollow Sentinel artifact creature token.
4. 4The Hollow Sentinel enters the battlefield, triggering Tainted Observer.
5. 5Holding priority, activate Ashnod's Altar by sacrifcing The Hollow Sentinel, adding .
6. 6Resolve the Tainted Observer trigger, causing you to pay to proliferate.
7. 7Repeat from step 3.

Effects

• Infinite creature ETB
• Infinite creature LTB
• Infinite creature sacrifice triggers
• Infinite death triggers
• Infinite proliferate