From Lexicanum

The Needle of Desire is a Daemon Weapon of Slaanesh.

Overview

The Needle of Desire is a double ended needle, one end of which is permanently inserted into the champion, from whom it absorbs various poisons and toxins produced by champions of Slaanesh. The venom will throw anyone into a state of delirium and many simply shut down the moment the toxins reach their blood stream, so potent is the poison. They will often then remain slumped over the needle.^{1-p56 2}

Sources

• ¹:Codex: Chaos Space Marines (3rd Edition, 2nd Codex), p56
• ²:Warhammer 40,000: Wargear