Here is a description of his powers.
Metallo’s metallic body offers him a high degree of protection from physical and energy attacks. He has enhanced abilities. Metallo no longer needs to eat, sleep or breathe. His brain is hermetically sealed inside a shielded alloy skull that has its own power supply. When he was first created he was powered by a Kryptonite heart. Also, as a result of his cyborg body, Metallo possesses superhuman strength and speed, enough to pose a challenge and even a threat to opponents such as Superman.Metallo sold his soul (or what was left of it) to Neron in order to gain the ability to absorb any mechanical or metal object he touches. He can transform any machine into an extension of his exo-skeleton(an ability similar to the Cyborg Superman).
Brainiac 13 upgraded Metallo to tap into light spectra and energy frequencies. Metallo also used the technology to upgrade his body to monolithic proportions.
He is also occasionally portrayed as having a liquid metal-based exoskeleton, possessing the ability to morph parts of his body, specifically his limbs, into different weapons or tools, such as chainsaws, shovels, hammers, etc.