Gutter Guardian

Keywords in this card's text

Hidden

On your turn in an open state, pay 1 Power of any domain to hide the card face-down at a battlefield you control that has no card hidden there.

From the next turn—including your opponent's—you can play it as a Reaction, ignoring its base cost. Additional costs still apply. It stays hidden there only while you control that battlefield. A hidden unit or Gear is played there; targets normally must be there too, unless the card explicitly requires a target elsewhere. You can instead play the card normally without hiding it.

Show Off

As you play the card, you may reveal a card from your hand that matches what it names, or pick a friendly one on the board that matches, whether a card or a token. Other text on the card then checks whether you showed off and can use details of what you showed off.

What you may show off is printed after the keyword, such as a unit or a card with a certain Energy cost, so the card's own text is the final word. The details of what you showed off are locked in at that moment, even if it later changes or leaves. Cards and effects cannot reference the front side of a facedown card, so it cannot be shown off for a trait printed there, such as the Hidden that Gutter Guardian asks for.