Spakthex, Omnidroid Miner

Skulk, crew 5
Whenever Spakthex, Omnidroid Miner attacks,
you may pay {x}. If you do, look at the top X
cards of your library. Put one into your hand
and the rest into your graveyard, then create two colorless Treasure artifact tokens with
"{t}, Sacrifice this artifact: Add one mana of any
color to your mana pool."