The Law of Givesies Backsies is respected by every noble pursuer of shiny things.

Das Täuschli-Pläuschli-Gesetz wird von allen ehrenhaften Jägern glitzernder Dinge respektiert.

Schatzmopser

Immer wenn ein Gegner ein Artefakt für Mana tappt, übernimm bis zum Ende deines nächsten Zuges die Kontrolle über das Artefakt.

Todo noble buscador de cosas brillantes respeta la regla del Trae Que Es Mío.

Ladronzuelo de tesoros

Siempre que un oponente gire un artefacto para obtener maná, gana el control de ese artefacto hasta el final de tu próximo turno.

とったらかえすの決まりは、ぴかぴかを求める高貴な者全員が遵守している。

宝捕り

対戦相手がマナを引き出す目的でアーティファクト１つをタップするたび、次のあなたのターンの終了時まで、あなたはそのアーティファクトのコントロールを得る。

离手不悔这规矩，每个醉心追逐闪亮东西的掠宝徒都会遵守。

掠宝鬼怪

每当任一对手横置一个神器以产生法术力时，你获得该神器的操控权直到你下一个回合的回合结束。

Treasure Nabber

Whenever an opponent taps an artifact for mana, gain control of that artifact until the end of your next turn.

Commander Masters

"Opposable thumbs, opposable toes, prehensile tails, boundary issues . . . no treasure is safe from a goblin."
—Captain Lannery Storm

To his dismay, he could not both fight and keep hold of his treasure.

Tales of Middle-earth Commander

Treasure Chest

If you control multiple Treasure Nabbers, their effects all expire at the same time. You won't keep an artifact for any longer.

An artifact is "tapped for mana" when a player activates a mana ability of an artifact that includes {T} (the tap symbol). Notably, tapping an artifact to pay for a spell with the improvise keyword is not tapping that artifact for mana.

If an opponent taps an artifact for mana during your turn, you'll gain control of it and keep control of it until the end of your next turn.

If multiple players each control Treasure Nabbers, an artifact tapped for mana will make quite a journey. For example, if player A taps an artifact for mana during their turn, and players B and C are the next players in turn order who control Treasure Nabbers, C's ability resolves before B and C gains control of the artifact. Then B gains control of the artifact. B keeps it during their turn, and then C regains control of the artifact once B's effect expires, then A will have it back after C's expires. However, if B or C taps the artifact for mana, one of them will take it from the other. You may need to pay very careful attention to which effects are still in effect, which have expired, and who owns what.

If the artifact leaves the battlefield, Treasure Nabber doesn't nab it from the zone it moved to.

In a multiplayer game, if a player leaves the game, all cards that player owns leave as well. If that player controls any nabbed treasures, the effect giving that player control of those artifacts ends.

The artifact remains tapped when you gain control of it.