BTG Stun Rifle

Dickie jerked and staggered back as a blackish-purple substance smacked and splattered across his chest. The gelatinous material spread out, covering his neck and shoulders. … Then, all at once, it dawned on us both. BTG. Ballistic Tasing Gel. The police affectionately called it “shock-snot.” It was nonlethal, delivered by a small, high velocity projectile. Nonlethal, but potent.
—Book 1, A Cold Blooded Rain, Chapter 33 – Worst-Case Scenario