Underhanded Designs

Text:

Whenever an artifact enters the battlefield under your control, you may pay . If you do, each opponent loses 1 life and you gain 1 life.
, Sacrifice Underhanded Designs: Destroy target creature. Activate only if you control two or more artifacts.

Rulings:

• 9/20/2016 You can pay <img src="/Handlers/Image.ashx?size=small&amp;name=1&amp;type=symbol" alt="1" align="absbottom" /> only once each time Underhanded Designs’s triggered ability resolves. You can’t pay more to cause your opponents to lose more life.
• 9/20/2016 The number of artifacts you control is checked only as you activate Underhanded Designs’s last ability. It’s not checked again as it resolves.
• 9/20/2016 In a Two-Headed Giant game, Underhanded Designs’s first ability causes the opposing team to lose a total of 2 life. You still gain only 1 life.