Chimeric Coils

Oracle Text

X1: Chimeric Coils becomes an X/X Construct artifact creature. Sacrifice it at the beginning of the next end step.

Card Rulings

12/1/2004 If X is 0, Chimeric Coils becomes a 0/0 creature and is put into its owner’s graveyard.
8/1/2008 A noncreature permanent that turns into a creature can attack, and its abilities can be activated, only if its controller has continuously controlled that permanent since the beginning of their most recent turn. It doesn’t matter how long the permanent has been a creature.