The Mizukage, the Giant Clam, and the Mirage

is episode 300 of the Naruto: Shippūden anime.

Summary
Gaara is sealing the Second Mizukage and the Third Raikage with sand in the form of his mother, but they escape. They begin ruthlessly attacking the Fourth Division. Meanwhile, Ōnoki and Mū simultaneously attack each other with their Particle Style: Atomic Dismanlting Technique. Mū warns him to call Gaara to use his Sensory-type techniques or Ōnoki, who as aged, will die. The Second Mizukage tries helping the Fourth Division by explaining his skills to them and how they can counter them. The Second summons his Giant Clam as the Third Raikage suggests to them to use Earth Style as a shield and Wind Style as an offence. He leaves as Temari and other wind and earth style Shinobi follow him. Gaara leaves leaving some of the other shinobi in charge, much to the Second Mizukage's disproval. Gaara arrives to help Ōnoki fight Mū, who has cast his Hiding with Camouflage Technique, who is not affected by his Rock Clones. He prepares to use the Particle Style again, but Naruto in his Nine Tails' Chakra Mode, arrives to help using his Planetary Rasengan. He misses since Mū is a sensory type, but he uses Gaara's sand to jump towards him again and blasts him away with the technique. Ōnoki quickly uses his Earth Release: Added-Weight Rock Technique to subdue him in the ground before Gaara seals him. He angrily asks Naruto why he is in the battlefield just as Shikaku speaks speaks to them and explains why Naruto's there. Gaara asks Naruto if he can handle using the Nine Tails' chakra so easily, and he answers that he doesn't plan to die until becoming Hokage, and is not a kid just because Gaara is Kazekage. He starts going to where the Third Raikage is as they go to the Second Mizukage. The shinobi there are still struggling to defeat the Second's genjutsu, and are attacked by his Water Balloon Technique before Gaara rescues them. However, the oil in the technique keeps weakening his sand. Gaara engages the Second while defending mostly. While doing so, he is secretively using his sand to find the real clam. Onoki then tries to blow it up, but he doesn't have enough chakra. He then uses his stone fist to break the clam's shell and its genjutsu. However, Onoki strains his back, allowing the Second to use his Water Gun technique to seemingly kill Onoki.

Credits
El Mizukage, una almeja gigante y los espejismos