Rock Hammer first appeared in Bakugan: New Vestroia episode 45 as a digital clone used by Spectra. Spectra attached it with Coredem (Jake's Guardian Bakugan). Rock Hammer consists of large double blasters that mount to a Bakugan's back and nullifies the opponent's Gate Card effect.

Ability Cards:

• Rock Hammer Beo-Blaster: Transfers 400 Gs from each opponent to Rock Hammer.
• Rock Hammer Battle Element: Transfers 500 Gs from the opponent to Rock Hammer.

Reference Cards:

• Ventus Effect: Move any Bakugan Gear or Trap to the used pile.
• Subterra Effect: Any Gate Card bonuses higher than 100 are lowered to 100.

Attributes:

• Gold 70 Gs
  
• Copper 70 Gs
  
• Silver 60 Gs

(Credits to bakugan.wikia.com for good information!)