Living Lore and Nim Deathmantle on the battlefield.
An opponent cannot block and kill Living Lore.
Living Lore does not have summoning sickness.
({4} magic symbol) each other turn available.
Steps
Deal combat damage to a player or permanent using Living Lore.
Living Lore triggers, causing you to sacrifice it.
When Living Lore dies, its reflexive ability and Nim Deathmantle trigger.
Resolve the Living Lore trigger, causing you to cast Time Stretch from exile without paying its mana cost.
Resolve Time Stretch, causing you to take two extra turns after this one.
Resolve the Nim Deathmantle trigger, causing you to pay ({4} magic symbol) to return Living Lore from your graveyard to the battlefield, and attach Nim Deathmantle to it.
As Living Lore enters the battlefield, choose to exile Time Stretch from your graveyard.