Thran Weaponry (Urza's Legacy 135) - Rare Magic: The Gathering Card

Echo (At the beginning of your upkeep, if this came under your control since the beginning of your last upkeep, sacrifice it unless you pay its echo cost.)
You may choose not to untap this artifact during your untap step.
, : All creatures get +2/+2 for as long as this artifact remains tapped.