Cast Fractured Identity by paying {3}{W}{U}, exiling Hivestone and causing each opponent to create a token copy of it.
Because each opponent controls a Hivestone, their creatures are all Slivers and cannot attack due to having defender, which is granted by Dormant Sliver.

Lock

Opponents can't attack

Dormant Sliver

Hivestone

Fractured Identity

Activate Vhal by tapping it, adding at least {C}{C}{C} that cannot be spent to cast spells from your hand.
Activate Vhal by paying {2}, untapping it.
Repeat.

Infinite colorless mana that can't be spent to cast spells from your hand

Infinite mana creatures you control can produce

Infinite untap of creatures you control

Vhal, Candlekeep Researcher

Scuttling Sliver

Draw a card.
The Locust God triggers, creating a 1/1 Insect creature token with flying and haste.
Activate the Insect by tapping it and discarding a card, causing you to draw a card.
Repeat from step 2.

Infinite draw triggers

Infinite rummaging

Infinite self-discard triggers

Near-infinite creature ETB

Near-infinite tapped creature tokens

The Locust God

Hollowhead Sliver

Activate Trazyn using Arc Reactor's ability by tapping it, adding {C}{C}{C}
Activate Trazyn by paying {2}, untapping it.
Repeat.

Infinite colorless mana

Trazyn the Infinite

Arc Reactor

Cast Wingmantle Chaplain by paying {3}{W}.
Wingmantle Chaplain's ETB ability and Dormant Sliver each trigger.
Resolve Dormant Sliver's trigger, drawing a card.
Resolve Wingmantle Chaplain's trigger, creating a 1/1 Sliver token with defender for each creature with defender you control.
Wingmantle Chaplain's last ability and Dormant Sliver each trigger once for each token created; put them on the stack in any order.
Resolve a Dormant Sliver trigger, drawing a card.
Resolve a Wingmantle Chaplain trigger, creating a 1/1 Sliver token with defender.
Repeat steps 5 through 7 until there are no cards in your library.
Put Wingmantle Chaplain's and Dormant Sliver's triggers on the stack in any order.
In response, cast Savage Summoning by paying {G}.
Cast Thassa's Oracle by paying {U}{U}.
Thassa's Oracle enters the battlefield and triggers.

Combos with "Hivestone"