fx = playfxontag(id, ent, tag);

fx = PlayFxOnTag(level._effect["bouledefeu"], level.model, "tag_origin");

//First, you need to pre-cache your fx file before init(). (Certain fx are pre-cached by default, there is a list in the forums here)
#precache("fx", "Symbo/test3");

function init()
{
	level flag::wait_till("initial_blackscreen_passed");
	level._effect["bouledefeu"] = "Symbo/test3"; //Defining the fx

	temp = struct::get("struct1", "targetname");
	//In radiant, put a new struct where the skull moves to - name it "destination"
	destination = struct::get("destination", "targetname");
	skull = Spawn("script_model", temp.origin);
	skull SetModel("p7_skulls_bones_head_02");
	skull.destination = destination.origin;

	temp Delete(); //If only using as an origin point - no longer needed
	destination Delete();

	fx_trigger = GetEnt("fx_trigger", "targetname");
	fx_trigger waittill("trigger");
	skull thread move_fx();
}

	//level.model enablelinkto();
	//level._effect["bouledefeu"] linkto(level.model);
	//***You do not call EnableLinkTo() on the fx ^ or the model here. The fx in gsc is only a string pointing to the fx file,
	//PlayFXOnTag() solves that, the fx will move with the model

function move_fx()
{
	PlayFXOnTag(level._effect["bouledefeu"], self, "tag_origin");
	//If you want to get fancy, you could make the skull look towards the destination point as it moves there
	//I wrote an easy function for that at the bottom of the page
	self face_target(self.destination);
	//Then move it there
	self MoveTo(self.destination, 2);

	//If feeling extra fancy you could make the skull 'look' at the nearest player
	while(1)
	{
		players = GetPlayers();
		searchDist = 500; //500 is the search distance for players - change as needed
		nearestPlayer = ArrayGetClosest(self.origin, players, searchDist);

		if(!isdefined(nearestPlayer) || Distance2D(self.origin, nearestPlayer.origin) > searchDist)
		{
			wait(1);
		}
		else
		{
			target = nearestPlayer GetTagOrigin("tag_eye");
			self face_target(target);
			wait(0.2);
		}
	}
}

//Syntax: <entity> face_target(<vector3>)
function face_target(target)
{
	vectorToFace = self.origin - target;
	angleToFace = VectortoAngles(vectorToFace);
	self RotateTo(angleToFace, 0.25);
}