The Space Pirates would introduce Phazon to anything and everything they thought to: Enhancing their weaponry, the flora and fauna of Tallon IV, and even Metroids (which they already sought to capture, cultivate, reproduce and harness).
Their researchers took extensive logs of the effects of Phazon on their specimens: Increased aggression, high rates of cell division, psychosis, and frequently, death. Nonetheless, they would force Phazon upon their own ranks, hoping to produce elite soldiers.