Rukir, Champion of Novgrod

First strike
Whenever Rukir, Champion of Novgrod deals
combat damage, create a colorless artifact token
named Gold. It has "Sacrifice this artifact: Add
one mana of any color."
{x}{b}{r}: Exile Rukir, Champion of Novgrod, then return him to the battlefield transformed under
his owner's control with X loyalty counters on it.