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In the Phazon Mines, there is a room called the Central Dynamo. Inside there will be an invisible creature whose weakness is the Power Beam. Once the creature is dead, go into the hole that is given to you using the morph ball and go through the electric maze and soon, without being electrocuted, you'll get the all powerful Power Bombs. Now you can destroy anything in Metroid Prime that is made of Bendezium, which will be useful in getting the X-Ray Visor and eventually fighting the Omega Pirate.