Locate the Phazon Source

With the Varia Suit equipped, you can now safely traverse the Geothermal Core. Your objective is to locate the primary Phazon source. Follow the objective marker, which will lead you through a labyrinth of volcanic caverns and Phazon-infused tunnels. You'll encounter new enemies like Phazon Hoppers and Magma Worms. Phazon Hoppers are agile; use lock-on and charged shots. Magma Worms are invulnerable to frontal attacks; wait for them to expose their glowing weak point. You'll eventually reach a large, open chamber with a massive Phazon deposit at its center. This is the source. Be prepared for a sificant environmental hazard here; the Phazon will periodically pulse, dealing damage if you're not careful. Scan the deposit to update your mission objectives.