An oyster monster awakened by Rita. He guarded his pearls of power. In battle, he could fire from the holes on his body an acidic gel that can burn through anything. He fought with the Megazord briefly underwater after growing on his own accord, where he had the upper hand. However, Dragonzord (who lived underwater) was able to knock him back onto dry land. Here, the Megazord was able to defeat him with the Power Sword.
Oysterizer was later used to guard the Rock of Time. He later attended Master Vile's End of the World party, appeared in the Machine Arena, and was one of many monsters featured in Countdown to Destruction. Oysterizer was also seen on Onyx as one of the monsters trying to bid on the Pink Quasar Saber, and was last seen in the Shadow World during the finale of Power Rangers: Lightspeed Rescue.
Note: Oysterizer comes from what is commonly referred to as "Zyu2" footage, and was not seen in the original ZyuRanger.