At the beginning of your upkeep, you may put a charge counter on this artifact.
: You may put a creature card with mana value equal to the number of charge counters on this artifact from your hand onto the battlefield.
Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
Haste (This creature can attack and as soon as it comes under your control.)
At the beginning of the end step, sacrifice this creature.