Activate Viscera Seer by sacrificing Nearheath Stalker
When Nearheath Stalker dies, its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
Resolve the Viscera Seer ability.
Activate Viscera Seer by sacrificing Nearheath Stalker
When Nearheath Stalker dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
Nearheath Stalker enters and dies as a state-based action due to having 0 toughness. Its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
Resolve the Viscera Seer ability from step 4.
Repeat from step 4.
This clever loop relies on the constant transformation of Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight to grant the crucial persist keyword to Nearheath Stalker, supplementing its native undying ability. By utilizing Viscera Seer as a reliable sacrifice outlet, you send the Stalker to the graveyard repeatedly. Whenever a +1/+1 counter and a -1/+1 counter cancel each other out through state-based actions, the opposing triggers reset, allowing you to cycle the Stalker infinitely between life and death for endless scries, enters-the-battlefield triggers, and sacrifices.