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Gibberslug (Ex): On a successful bite attack, a brood gibberling may attempt to insert a gibberslug into the victim. The victim must succeed on a DC X Reflex(?) save. If the save fails, each round thereafter the target takes 1d4 points of damage as the slug bores its way toward the brain. The save DC is Constitution-based.
A gibberslug will reach a creature's brain in 1d6+5 rounds, at which point the host automatically falls into a coma, subject to alien nightmares which ravage its mind. After 1d20+4 hours, the gibberslug completely digests the hosts brain and body from within, and a fully grown gibberling emerges from the husk. Although the gibberling slightly resembles the victim, it retains no memory of its former life and immediately attacks any non-gibberlings it finds.
In the round following entry, fire can be applied to the gibberslug's point of entry to kill the gibberslug, but this also deals 1d4 points of fire damage to the host. Before it reaches the brain, a gibberslug can be destroyed with a remove disease, heal, or similar effect, or by ingesting a special form of mushroom called Darkscape that grows in regions tainted by the Far Realm. Once the gibberslug has reached the brain, no form of ressurection will work on the body, although a wish or a miracle spell can restore the victim to life and its original form, destroying the gibberslug.
Spit Gibberslug (Ex): Once ever 1d4 rounds, a brood gibberling can spit a gibberslug at a target. This requires a ranged attack and has a range increment of 10 feet. On a successful hit, the victim must make a saving throw as normal for the gibberslug ability (see above).