Spiraling Duelist
Creature — Human Berserker
Metalcraft — This creature has double strike as long as you control three or more artifacts.
"I never move the same way twice. Those rotters can't grasp chaos."
Karl Kopinski
Mirrodin Besieged (MBS)
• #76Rulings
If Spiraling Duelist has double strike as the combat damage step begins, there will be a second combat damage step. As that second combat damage step begins, if Spiraling Duelist no longer has double strike (perhaps because an artifact creature you controlled was destroyed), Spiraling Duelist will not assign combat damage a second time.
(wotc • 2011-06-01)
Rulings
If Spiraling Duelist has double strike as the combat damage step begins, there will be a second combat damage step. As that second combat damage step begins, if Spiraling Duelist no longer has double strike (perhaps because an artifact creature you controlled was destroyed), Spiraling Duelist will not assign combat damage a second time.
(wotc • 2011-06-01)