gzdoom/wadsrc/static/zscript/shared/mapmarker.txt

class MapMarker : Actor native
{
	default
	{
		+NOBLOCKMAP
		+NOGRAVITY
		+DONTSPLASH
		+INVISIBLE
		Scale 0.5;
	}
	States
	{
	Spawn:
		AMRK A -1;
		Stop;
	}
}