Strictly speaking, parasites live on other living things, but you can extend the concept by straightforward analogy to things that live on and extract nutrition from equipment (often to the detriment of the equipment). Such exotic "parasites" can play an interesting role in roleplaying games.

From mundane shipworms that bore into and weaken wood-hulled ships, to psionic parasites that feed off the intelligence of wizards, the possibilities are limitless. There can be magical parasites that leach the abilities from magical weapons or other items. And high-tech parasites that suck electrical or other power from gadgets and vehicles. You don't even need to be quite so exotic. A creature that eats metal or plastic can be just as bad on a modern vehicle as one that eats gamma radiation energy, if that metal or plastic is part of a power conduit or computer system.

Transcript

Leia: I'll scan the cave through the window.
GM: Spot check.
Leia: 18.
{an animal thing appears, stuck on the window}
[SFX]: Splat!
[SFX]: Gllraaawwk!
Leia: O-kay then. Do I recognise it? 13 for Knowledge.
GM: It's a mynock, a bat-like space-faring parasite.
Leia: Parasite? {walks to see Han}
Han: What's up, Princess?
Leia: There's a parasite on the ship, we have to get rid of it.
Han: But Chewie's still welding.
Leia: I think this is more important.
Han: Relax. We'll dump him after he's finished.
Chewbacca: You know... I have no idea whether you're joking or not.
Han: No, seriously, I'll let you finish.