The Aetherspark

As long as The Aetherspark is attached to a creature, The Aetherspark can't be attacked and has "Whenever equipped creature deals combat damage during your turn, put that many loyalty counters on The Aetherspark."

Loyalty +1: Attach The Aetherspark to up to one target creature you control. Put a +1/+1 counter on that creature.

Loyalty -5: Draw two cards.

Loyalty -10: Add ten mana of any one color.