Elderly Alchemist

At the beginning of your upkeep, you may pay {r}. If you do, put a progress counter on Elderly Alchemist. Then, if there are three or more progress counters on Elderly Alchemist, sacrifice it, destroy target artifact, and create a colorless Gold artifact token with "Sacrifice this artifact: Add one mana of any color."
"At last, I have perfected alchemy! I have turned all
my metal into gold. This is truly my finest day."
-Laboratory Notes, volume III, final entry