Inchell Xyrro, Undercity Thief

Skulk
Attune with Fangs of The Night
When Inchell Xyrro, Undercity Thief enters
the battlefield you create X colourless Treasure artifact tokens with "{t}, Sacrifice this artifact:
Add one mana of any colour." Where X is the
number of artifacts in your opponents graveyards.
"Sorry, finders keepers!"