Captain Spark

You may sacrifice three artifacts instead of
paying Captain Spark's mana cost.
Metalcraft—{w/u}{w/u}You may exile Captain Spark.
Return it to the battlefield under your control at
the beginning of the next end step. Activate only
if you control three or more artifacts.
Whenever Captain Spark enters the battlefield, shuffle three tokens in target opponent's library.
When a token is drawn, your creatures gain
+5/+0, vigilance, and indestructible until your
next end step.