Rust Tick (SOM) from Scars of Mirrodin, available at 401 Games Canada.

• Rarity: Uncommon
• Finish: Normal
• Artist: Carl Critchlow
• Card Text:
  You may choose not to untap Rust Tick during your untap step.
  1, T: Tap target artifact. It doesn't untap during its controller's untap step for as long as Rust Tick remains tapped.