Rusko, Clockmaker

When Rusko, Clockmaker enters the battlefield, conjure a card named Midnight Clock onto the battlefield.
Whenever you cast a noncreature spell, put an hour counter on each permanent you control named Midnight Clock. Each opponent loses 1 life and you gain 1 life.

Mystery Booster 2

Alchemy: The Brothers' War

A conjured card’s owner is the player who was instructed to conjure it.

Conjured cards are not tokens. Treat conjured cards just as you would treat regular cards. They can move between zones just like any other card and continue to exist for the duration of the game. At the end of the game, make sure to remove all conjured cards from your deck.

Rusko’s last ability resolves before the spell that caused it to trigger. It resolves even if that spell is countered.

To conjure a card in a game of tabletop Magic, use the Gatherer card database at Gatherer.Wizards.com to find the official text for the card you’re conjuring. Then put the appropriate conjured card into the appropriate zone.

You can represent conjured cards using objects from outside the game so long as the game state remains clear and understandable to all players. You might need to get creative. For example, while a conjured card is in a public zone, you can represent it by writing on a piece of paper or using some kind of token. But if a conjured card is put into a hidden zone, you must add an object to that zone which, while face down, is indistinguishable from other cards in your deck.

You do not need to own an actual copy of a card in order to conjure it, and a conjured card does not need to obey format legality or deckbuilding restrictions. For example, in a game of Mystery Booster 2 Limited, Toralf’s Disciple can conjure Lightning Bolts into your deck, even though the card Lightning Bolt isn’t found in Mystery Booster 2 and isn’t normally legal in the Limited format.