The Proto-Corruption (officially designated Project SO-6, and derivatively nicknamed "Oilblot" by those that fought it) was a biological experiment by mad Dark Jedi Aherk Formidonis, and his masterpiece over the creation of life, created from ysalamiri, Yuuzhan Vong, and orbalisk DNA. Initially intended to bolster the abilities of Force users, its side effects proved too malignant to make it truly useful, and it was shelved until used in an insane, bloody attack on the Jedi Temple on Coruscant. After a long time in operation, bonding to several hosts, the beast was slain on Dantooine.
Project SO-6 was originated on Kamino, where the mad scientist Aherk Formidonis sought a way to augment his mediocre Force potency, with the hope of enabling him to best stronger opponents, while at the same time negating their own Force power. Starting by studying the properties of ysalamiri, which neutralized the Force surrounding it, and sending his personal droid KR-03 to capture a Yuuzhan Vong (a species also noted for their immunity and existence outside of the Force), Formidonis worked for months until he found a potent combination that utilized the best elements of both species. The comparatively simple solution, when tested, negated all influence from the Force surrounding it.
Having developed a way to negate the powers of other Force-users, Formidonis' next step was to find a way to keep it from cancelling out his own. Traveling to Dxun, the Dark Jedi captured an orbalisk and brought it back to Kamino, dissecting it and studying it; how it augmented the Force of the user, how it fed off of the midichlorians of the host, and how the relationship between parasite and host worked on a cellular level.