Sliver Queen + Agatha of the Vile Cauldron + Phyrexian Altar

Sliver Queen

Agatha of the Vile Cauldron

Phyrexian Altar

How it works

1. Activate Silver Queen by paying 1, creating a 1/1 Sliver creature token.
2. Activate Phyrexian Altar by sacrificing the Sliver, adding 1.
3. Repeat.

This loop turns Sliver Queen into a self-sustaining engine by taking advantage of Agatha of the Vile Cauldron's cost-reduction ability, which lowers the Queen's token-creation cost down to just a single mana. Once that token hits the board, you simply feed it directly to Phyrexian Altar to sacrifice the Sliver and recoup the exact mana you spent, generating an endless loop of entries, exits, and sacrifices. Because Agatha of the Vile Cauldron can reduce abilities down to a minimum of one mana, this interaction bypasses the Queen's normal price tag to cleanly generate infinite triggers for any deck resilient enough to harness them.