Key

[["[[Artifact type|Artifact Type]]",[{"data":"([[Subtype]] for [[artifact]] cards)"},{"data":"''[[Mystery Booster]]''","label":"Introduced"},{"data":"''[[Mystery Booster]]''","label":"Last used"}]],["Scryfall Statistics",[{"data":"[https://scryfall.com/search?q=type%3A%2F%5CbKey%5Cb%2F+include%3Aextras cards]"},{"data":"[https://scryfall.com/search?q=art%3A%22Key%22 artworks]"}]]]

Key
Artifact Type
(Subtype for artifact cards)
Introduced	Mystery Booster
Last used	Mystery Booster
Scryfall Statistics
cards
artworks

Key is an artifact type introduced in Mystery Booster on a Test card.

Description

Key appears on the Corrupted Key test card as an artifact type. It currently has no rules meaning or function by itself, but other cards and abilities may refer to it. Corrupted Key grants an ability to creatures when tapped but cannot be tapped on its own, instead its rules mention that it needs another card to tap it or “turn the key”.