NPC #32768 (possibly named "Invisible Stalker Floating Uninteractible Large Sessile Custom Phase 2") doesn't exist. It may have been removed from the game.
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Invisible Stalker (Floating, Uninteractible, Large, Sessile, Custom Phase 2) - Live
Invisible Stalker (Floating, Uninteractible, Large, Sessile, Custom Phase 2) - PTR
Invisible Stalker (Floating, Uninteractible, Large, Sessile, Custom Phase 2) - PTR 2
Invisible Stalker (Floating, Uninteractible, Large, Sessile, Custom Phase 2) - Beta
Invisible Stalker (Floating, Uninteractible, Large, Sessile, Custom Phase 2) - Wrath of the Lich King
Invisible Stalker (Floating, Uninteractible, Large, Sessile, Custom Phase 2) - Cataclysm