Mynocks are parasitic species of bat-like creatures from the world of Ord Mynock. They were silicon based and enjoyed chewing the power cables and energy conductors of starships to drain the power supply.
They appeared in The Empire Strikes Back, where they did the exact same as explained above to the Millennium Falcon when Leia and Han were stranded within a meteorite worm. Leia had spotted them when she was in the cockpit.