I have this installed and have yet to see a single NPC from it. I saw the following in the logs, not sure if this is related:
03:29 [Error] Failed to call hook 'OnEntitySpawned' on plugin 'PumpkinHead v1.1.7' (NullReferenceException: Object reference not set to an instance of an object)
at Oxide.Plugins.PumpkinHead.OnEntitySpawned (NPCPlayerCorpse corpse) [0x00041] in <fa969b6a19894105b22ffaafcc4944df>:0
at Oxide.Plugins.PumpkinHead.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x0023e] in <fa969b6a19894105b22ffaafcc4944df>:0
at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <cd9a02fd331347bd82d550bb1a9c8e9f>:0
at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000d8] in <b76ec77c47d1449e92b2baab8603843d>:0
at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in <b76ec77c47d1449e92b2baab8603843d>:0
03:29 [Error] Failed to call hook 'OnEntitySpawned' on plugin 'PumpkinHead v1.1.7' (NullReferenceException: Object reference not set to an instance of an object)
at Oxide.Plugins.PumpkinHead.OnEntitySpawned (NPCPlayerCorpse corpse) [0x00041] in <fa969b6a19894105b22ffaafcc4944df>:0
at Oxide.Plugins.PumpkinHead.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x0023e] in <fa969b6a19894105b22ffaafcc4944df>:0
at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <cd9a02fd331347bd82d550bb1a9c8e9f>:0
at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000d8] in <b76ec77c47d1449e92b2baab8603843d>:0
at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in <b76ec77c47d1449e92b2baab8603843d>:0
03:29 [Error] Failed to call hook 'OnEntitySpawned' on plugin 'PumpkinHead v1.1.7' (NullReferenceException: Object reference not set to an instance of an object)
at Oxide.Plugins.PumpkinHead.OnEntitySpawned (NPCPlayerCorpse corpse) [0x00041] in <fa969b6a19894105b22ffaafcc4944df>:0
at Oxide.Plugins.PumpkinHead.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x0023e] in <fa969b6a19894105b22ffaafcc4944df>:0
at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <cd9a02fd331347bd82d550bb1a9c8e9f>:0
at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000d8] in <b76ec77c47d1449e92b2baab8603843d>:0
at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in <b76ec77c47d1449e92b2baab8603843d>:0
03:29 [Error] Failed to call hook 'OnEntitySpawned' on plugin 'PumpkinHead v1.1.7' (NullReferenceException: Object reference not set to an instance of an object)
at Oxide.Plugins.PumpkinHead.OnEntitySpawned (NPCPlayerCorpse corpse) [0x00041] in <fa969b6a19894105b22ffaafcc4944df>:0
at Oxide.Plugins.PumpkinHead.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x0023e] in <fa969b6a19894105b22ffaafcc4944df>:0
at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <cd9a02fd331347bd82d550bb1a9c8e9f>:0
at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000d8] in <b76ec77c47d1449e92b2baab8603843d>:0
at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in <b76ec77c47d1449e92b2baab8603843d>:0