Armageddon Clock [Antiquities] SWSH065 Must first be Special Summoned

Must first be Special Summoned (from your hand) by Tributing 1 "Petit Moth" on your 6th turn or later after it was equipped with "Cocoon of Evolution"

Whenever Ma Chao

return it to the battlefield under its owner's control with a -1/-1 counter on it

Send 1 monster card from your hand to the Graveyard to destroy all face-up monsters on your opponent's side of the field with an ATK equal to or less than the ATK of the sent monster

While you control another "Number" Xyz Monster

Armageddon Clock [Antiquities] SWSH065 Must first be Special SummonedSet: Antiquities Type: Artifact Rarity: Uncommon Cost: {6} At the beginning of your upkeep, put a doom counter on Armageddon Clock. At the beginning of your draw step, Armageddon Clock deals damage equal to the number of doom counters on it to each player. {4}: Remove a doom counter from Armageddon Clock. Any player may activate this ability but only during any upkeep step.