Unstoppable Slasher + Solemnity + Phyrexian Altar

Unstoppable Slasher

Solemnity

Phyrexian Altar

How it works

1. Activate Phyrexian Altar by sacrificing Unstoppable Slasher, adding one mana of any color.
2. When Unstoppable Slasher dies, its second ability triggers, returning it from your graveyard to the battlefield with zero stun counters due to Solemnity.
3. Repeat.

This loop turns Phyrexian Altar into an infinite mana generator by exploiting how Solemnity completely shuts down Unstoppable Slasher's safety valve. Normally, sacrificing the Slasher to the Altar would cause it to return with pesky stun counters that halt the engine, but Solemnity prevents those counters from ever being placed. With no counters to impede it, the Slasher returns fresh to the battlefield every single time it dies, letting you endlessly sacrifice it to fuel your mana pool while generating an infinite stream of sacrifice and death triggers.