Quicksilver Amulet
Artifact
, 
: You may put a creature card from your hand onto the battlefield.
Those who examine the amulet too closely have been known to become part of its ornate carvings.
Brad Rigney
Rulings
You don't pay any costs of that creature card, including additional costs.
(wotc • 2011-09-22)
Putting the card onto the battlefield is optional. When the ability resolves, you can choose not to.
(wotc • 2007-05-01)
Any 'X' in the creature's cost is treated as zero.
(wotc • 2004-10-04)
Rulings
You don't pay any costs of that creature card, including additional costs.
(wotc • 2011-09-22)
Putting the card onto the battlefield is optional. When the ability resolves, you can choose not to.
(wotc • 2007-05-01)
Any 'X' in the creature's cost is treated as zero.
(wotc • 2004-10-04)