Artifact spells you cast have convoke. (Your creatures can help cast those spells. Each creature you tap while casting an artifact spell pays for or one mana of that creature's color.)

When you cast this spell, reveal the top X cards of your library. You may put a nonland permanent card with mana value X or less from among them onto the battlefield. Then shuffle the rest into your library.
This creature enters with X +1/+1 counters on it.

When this creature enters, you may destroy target artifact or enchantment.

Whenever you draw a card, put a +1/+1 counter on this creature.
When this creature dies, create X 1/1 blue Squid creature tokens with islandwalk, where X is the number of +1/+1 counters on this creature. (They can't be blocked as long as defending player controls an Island.)

Other Goblin creatures you control attack each combat if able.
At the beginning of combat on your turn, create a 1/1 red Goblin creature token with haste.
Whenever this creature attacks, it gets +1/+0 until end of turn for each other attacking Goblin.

Flying
At the beginning of your upkeep, draw a card unless target opponent sacrifices a creature of their choice or pays 3 life.

You may have this creature enter as a copy of a creature you control, except it has ": Return this creature to its owner's hand."

When this creature dies, return it to the battlefield tapped under its owner's control at the beginning of their next upkeep.

Flying, trample
Whenever an opponent searches their library, that player sacrifices a creature of their choice and loses 10 life.
Whenever another creature dies, put a +1/+1 counter on Ob Nixilis.

Trample
: Permanents you control gain indestructible until end of turn.
, Exile this card from your graveyard: Permanents you control gain indestructible until end of turn.

Flying
When this creature enters, destroy all Walls your opponents control.
Whenever this creature attacks, if defending player controls no Walls, it deals 2 damage to each creature without flying that player controls.

Flying
When this creature enters, if your life total is less than your starting life total, it becomes equal to your starting life total.

Destroy all creatures you don't control and all planeswalkers you don't control.