Rampant 343 Guilty Spark

Flying, Unstable 3 (this artifact enters with 3 counters. At the beginning of your upkeep, remove a counter. If it has no counters, sacrifice it)
Guilty spark attacks each combat if able.
Whenever a Sentinel enters the battlefield, you may put a unstable counter on target creature with unstable.
When Rampant 343 Guilty Spark is dies, destroy target artifact.