Abuelo, Ancestral Echo | Ugin's Nexus

Cards

({4} magic symbol) ({W} magic symbol) ({W} magic symbol) ({U} magic symbol) ({U} magic symbol) available the first turn, with ({3} magic symbol) ({W} magic symbol) ({U} magic symbol) available each extra turn available.

Activate
Abuelo by paying ({1} magic symbol) ({W} magic symbol) ({U} magic symbol) , exiling
Ugin's Nexus until the beginning of the next end step.
At the beginning of your end step,
Abuelo triggers, returning
Ugin's Nexus from exile to the battlefield.
When
Ugin's Nexus enters the battlefield,
Mirrorworks triggers, causing you to pay ({2} magic symbol) to create a token copy of
Ugin's Nexus.
Put the token
Ugin's Nexus into exile due to the legend rule and its replacement effect, causing you to take an extra turn after this one.
Activate
Abuelo by paying ({1} magic symbol) ({W} magic symbol) ({U} magic symbol) , exiling
Ugin's Nexus until the beginning of the next end step.
Move to your next turn, not skipping it as
Ugin's Nexus is not on the battlefield.
Repeat from step 2.

This combo has been estimated to be Ruthless (Bracket 4+).