Molderhulk | Cloudstone Curio | Dual Nature (and one other card)

Cards

You control at least one Swamp and at least one Forest that enter the battlefield untapped.
You have at least seven creature cards in your graveyard.
You have at least one Swamp card and at least one Forest card that enter the battlefield untapped in your graveyard.

Activate a Swamp and Forest by tapping them, adding ({B} magic symbol) ({G} magic symbol) .
Cast
Molderhulk by paying ({B} magic symbol) ({G} magic symbol) .
When
Molderhulk enters the battlefield, it,
Dual Nature's first ability and
Cloudstone Curio trigger.
Resolve the
Cloudstone Curio trigger, choosing to return nothing to your hand.
Resolve the
Dual Nature trigger, creating a token copy of
Molderhulk.
When the
Molderhulk token enters the battlefield, it and
Cloudstone Curio trigger.
Resolve the
Cloudstone Curio trigger, returning the nontoken
Molderhulk from the battlefield to your hand.
When the nontoken
Molderhulk leaves the battlefield,
Dual Nature's second ability triggers, exiling the token
Molderhulk.
Resolve the token
Molderhulk's trigger from step 6, returning a Swamp from your graveyard to the battlefield.
When the Swamp enters the battlefield,
Cloudstone Curio triggers, returning another Swamp from the battlefield to your hand.
Resolve the nontoken
Molderhulk's trigger from step 4, returning a Forest from your graveyard to the battlefield.
When the Forest enters the battlefield,
Cloudstone Curio triggers, returning another Forest from the battlefield to your hand.
Activate
Borborygmos Enraged twice by discarding the Swamp and Forest, dealing 6 damage to any target.
Repeat.

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