Haunted Crossroads, Phyrexian Altar, Sunshower Druid, and Bolas's Citadel

Prerequisites

• Haunted Crossroads on the battlefield
• Phyrexian Altar on the battlefield
• Sunshower Druid in hand or in the library
• Bolas's Citadel on the battlefield
• if Sunshower Druid is in your hand available

Steps

1. Cast Sunshower Druid either from your hand by paying or from the top of your library by paying 1 life
2. When Sunshower Druid enters, it triggers, putting a +1/+1 counter on a creature and causing you to gain 1 life
3. Activate Phyrexian Altar by sacrificing Sunshower Druid, adding
4. Activate Haunted Crossroads by paying , putting Sunshower Druid from your graveyard onto the top of your library
5. Repeat

Results

• Infinite +1/+1 counters on a creature
• Infinite ETB
• Infinite lifegain
• Infinite sacrifice triggers