Goblin Biker Grand Pileup

Target 1 Xyz Monster you control; Special Summon 1 "Goblin" Xyz Monster from your Extra Deck, using that monster you control as material, and if you do, attach this card to it as additional material. (This is treated as an Xyz Summon.) You can banish this card from your GY, then target 1 "Goblin" Xyz Monster you control and 1 card in either GY; attach the second target to the first target as material. You can only use each effect of "Goblin Biker Grand Pileup" once per turn.