yugioh zoodiac cards RA04-EN091 - Barrage - Quarter Century Secret Rare Warrior and has this card as Xyz Material gains this effect ZOODIAC Deck Profile (Post Spetember

It doesn't matter if Oko leaves the battlefield before the ability resolves or later in the turn

Once per turn: You can banish 1 random card from your opponent's hand face-down, until your opponent's next End Phase

And, even if the opponent isnt completely wiped out right away, its a source of continuous damage

Choose 1 of your opponent's face-down Prizes

If Ugins Labyrinth is indeed S tier, it will likely be in conjunction with Devourer of Destiny to get up to enough playable 7 drops to consistently get 2 mana off the Labyrinth

Legality depends on the tournament format -- Seed of Deception can be legal in some formats and banned or restricted in others