The Parasitic Rods are referred to the projectiles shot from The Destroyer. The rods themselves can either take over their host (Whoever they hit) or transform on their own. A few characters have destroyed the rods before they can have an effect on them (Priscilla, Deneve), so it is possible to resist them.
Parasitic Rods were first seen and used in Claymore Chapter 94. The Destroyer has the ability to shoot out these rods which cause much destruction. They appear to be slightly larger than Isley's arrows when he was in his awakened form, being taller than a two story house as seen in the town Raki was at when it was hit.
The Luciela-like creatures spawned from the rods are able to also shoot out more rods themselves (though on a much smaller scale), they also appear to have a limited life span dying off after their Yoki runs out. It's estimated they can live for a day or two before running out of Yoki, though the only known ones were in battle the whole time so left on their own may be able to last longer.
These creatures might be less considered independent entities and more simply part of The Destroyer itself, such as how Dauf's projectiles are formed from his body.
InfectedEditThose hit with the rods (Either the Destroyer's or the Creature's) have had different results but undergo some form of transformation.
Beth was hit through the stomach with one of the Destroyer's rods, and the rod forced her to Awaken, altering her Awakened form as it assimilated her. The effect was akin to her awakening and, despite a critically altered form, retained herself. She also wept at the death of her sister.
Dauf when infected became an enraged and uncontrollable monster. His Awakened form changed slightly giving him a more skeletal look. It was implied by Priscilla he deliberately let himself get infected by the rods. Whether from the effect of the rodes or his own rage, Dauf mentally changed into a feral beast, even allowing Riful's remains to be harmed, only able to target Priscilla. The rods seemed to increase and restore his lost strength, and managed to, if very temporarily, overpower Priscilla.
Raki was hit by the rod's but resisted the transformation with the aid of Priscilla's severed arm, which she imbedded in his back. The arm was later removed by the Organization, along with the rods as material to revive three of the most powerful Claymores as new Creatures of the Abyss; thus Raki was spared.
Unlike the others the effect the rods have on the Abyss Feeder 's has no physical characteristics. However infection drives them into a ravenous frenzy, overpowering any psychological blocks established.
Priscilla was seemingly immune to the rods infectious properties do to her immense level of Yoki. However, she was absorbed into The Destroyer itself.