Cast Fractured Identity by paying {3}{W}{U}, exiling Maskwood Nexus and causing each opponent to create a token copy of it.
Because each opponent controls a Maskwood Nexus, 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

Maskwood Nexus

Fractured Identity

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.

Hivestone

Draw a card.
The Locust God triggers, creating a 1/1 Insect creature token with flying and haste.
The Insect enters the battlefield with all creature types due to Maskwood Nexus, causing you to draw a card.
Repeat from step 2.

Infinite card draw

Infinite draw triggers

Near-infinite creature tokens with haste

Near-infinite creature ETB

The Locust God

Arcane Adaptation

Xenograft

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 "Dormant Sliver"