Making a headcrab xen teleport

This guide will teach you how to make an npc (in this case a headcrab) teleport in-front of the player as seen throughout the campaign

Skill Level This tutorial expects you to have this amount of knowledge within the topic to follow along smoothly.
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Trigger Construction

The trigger

Start by creating a brush that uses the tools/toolstrigger texture
Next tie it to a trigger_once by pressing control + T

The trigger brush tied to a trigger_once

The trigger logic

Now in the outputs add the following:

	My Output	Target Entity	Target Input	Parameter	Delay	Only Once
	OnStartTouch	xen_spawner	Spawn		0.00	No

The xen portal

Place a env_xen_portal with the following properties:

Property Name	Value
Name	xen_spawner
Frequency	-1
Max Live NPCs	1
Class name of spawned NPC	npc_headcrab

You may edit the Class name of spawned NPC parameter to change the desired npc, note that they are usually xen creatures. Note: you may play around with the Frequency, Max Live NPCs parameters!

Warning:Be careful of the Max Live NPCs and Frequency parameters, if you don't know what you are doing then leave it as the above values

Final Setup

Your final setup should look like this;

The final result: