WormBlend

The WormBlend is an unused Implant found only in the game files of System Shock 2. It renders the player entirely invisible to all pure Annelids (including Swarms), even when they are attacked! Note that Annelid Eggs will still open up when approached, but the spawned Grubs and Swarms won't detect us. It burns up 1% of its charge every 10 seconds.

This Implant contains a portion of annelid neural tissue, with electrochemical connections to slave the tissue to the user's neural impulses. The portion of tissue is not substantive enough to allow the user to psionically contact the annelid mind, but it does coordinate the user's brainwaves enough with the annelid neural processes that the user will, to a cursory psionic examination, resemble an annelid organism. This will very likely allow its user to become harder to detect to annelid creatures.

Analysis

 * Contrary to what both the Summary and Recommendation of this Implant say, the player becomes fully invisible to all pure Annelid creatures (Grubs, Swarms, Arachnids, Psi Reavers), even when swinging melee weapons, firing shots or using Psi powers - at any target, including those Annelids! Even killing them won't alert the other ones in any way!
 * However, discharging or detaching this Implant - even for a brief moment - will result in the Implant not working at all, even in the case of pure Annelids that we haven't encountered yet, on the farthest end of the same map. Saving and loading the game does not change this. The solution in this case is to exit the map (through a Bulkhead etc.) and re-enter. The implant will once again work as a charm.
 * While this Implant works astonishingly well for pure Annelids (it probably wasn't placed in the game itself because it wasn't balanced enough ; after all, it's descripted as "not allow[ing] the user to pass for an Annelid in face-to-face contact."), it does not work at all for half-Annelids or any other types of enemies.
 * This item must be researched before it can be used, requiring Research skill level 2 and a small amount of Arsenic.
 * The higher your Maintenance skill is, the more charge you can store in the Implant.
 * Using this Implant is especially recommended in the Body of the Many, with its abundance of pure Annelids and the presence of the only Greater Psi Reaver in the game. However, half-Annelids need to be taken care of traditionally, so the Rumblers will still be on your tail.