When Wormfang Drake enters, its first ability triggers, exiling Sister Hospitaller.
Activate Woe Strider by sacrificing Wormfang Drake.
When Wormfang Drake dies, its second ability triggers, returning Sister Hospitaller from exile to the battlefield.
When Sister Hospitaller enters, it triggers, returning Wormfang Drake from your graveyard to the battlefield.
When Wormfang Drake enters, its first ability triggers, exiling Sister Hospitaller.
Resolve the Woe Strider ability.
Repeat from step 3.
This clever loop relies on an infinite recursion between Wormfang Drake and Sister Hospitaller, where each creature constantly rescues the other from the grave or exile. Whenever Wormfang Drake enters the battlefield, its sacrifice trigger exiles Sister Hospitaller, but the moment you sacrifice the Drake to Woe Strider's claw, the Sister returns—which immediately triggers her own ability to fish the Drake right back out of your graveyard. Meanwhile, Woe Strider quietly turns this endless cycle into a bottomless well of scry triggers, letting you sift through your entire library while keeping you healthy with infinite lifegain from the Hospitaller.