Nim Deathmantle | Ashnod's Altar | Tangled Colony (and one other card)

Cards

Activate
Ashnod's Altar by sacrificing
Tangled Colony, adding ({C} magic symbol) ({C} magic symbol) .
When
Tangled Colony dies, it and
Nim Deathmantle triggers.
Resolve the
Nim Deathmantle trigger from step 2, causing you to pay ({4} magic symbol) to return
Tangled Colony from your graveyard to the battlefield, and attach
Nim Deathmantle to it.
When
Tangled Colony enters the battlefield,
Warstorm Surge triggers, dealing damage equal to
Tangled Colony's power to any target.
Resolve the
Tangled Colony trigger, creating a 1/1 Rat creature token.
When the Rat enters the battlefield,
Warstorm Surge triggers, dealing 1 damage to
Tangled Colony.
Activate
Ashnod's Altar by sacrificing the Rat, adding ({C} magic symbol) ({C} magic symbol) .
Repeat.

This combo has been estimated to be Exhibition (Bracket 1+).