The sieka(named for a type of tick found in the wastelands of Acheron) is extremely tiny, barely the size of an ant or ladybug and, due to its bright blue coloring and segmented, mite-like body, it is often taken to be a strange insect. It is not, however, a harmless bug. These tiny creatures usually live alone in tiny burrows until they can find a host body to inhabit. They fly on tiny wings and bite into the flesh of a creature, usually a humanoid or animal. Their teeth are so fine that the bitten creature rarely notices..
Once it has latched on, they begin to burrow into the body, working their way to a vein or artery and from there to an organ. The sieka will then attach itself to the wall of the organ, slowly growing a cucoon and feeding off the blood of the host via small tendrils inserted into the organ’s lining. The host has no symptoms to give away its miniscule passenger. The sieka’s cucoon slowly grows larger, becoming the size of a golfball, then as large as an ostrich egg. Once it grows to this size, a transformation which takes months or even a couple years, during which the host suffers no ill-effects until near the end, the creature spontaneously bursts from its host, rupturing the organ and exploding through flesh. The sieka then flys away on much stronger wings, the creature now as big as a pair of human fists.
After this metamorphosis, the sieka becomes as a locust, though with a lust for blood, rather than crops. It will seek out others of its kind and then in a massive swarm, they will descend upon an area, wipe it clean of all animal life, then continue to somewhere else. These swarms of sieka are rare, since the creatures don’t usually live very long. Peasants and nobles alike know to kill one as soon as they see it, but every few decades, a large population of the sieka will form and leave only ruin and devestation in their wake.