What Butters says is true. But there are some "Psuedo" ways to get what you're looking for.
Put this script into your ghost entity (I'm guessing that's what you're going after, if not it'll work just the same):
:state=0,random=100:spawnon,state=1
:state=1:floatrate=1,rotatetoplr
:state=1,random=100:state=2
:state=2:runfpidefault=2
(Sorry, Butter Fingers, I slightly modified your code so that I wouldn't have to come up with a new one, lol)
Now set these properties for your entity:
Spawn At Start = "No"
Max at any time = 1
Maximum Spawn = 9999 (Or just something high)
Spawn after delay = "No"
Spawn when dead = "No"
Number to spawn = 1
Strength = 0 (Or, if you want it to be killable, give it a number for it's health)
Physics On = "No"
Now, put this entity in lots of different locations around the room. They will spawn at seemingly different times, and it will appear to be randomly spawned! Also, the entity will always face towards the player... kinda creepy really. If you don't want the entity to face the player just remove the ",rotatetoplr" part of the code.
For a different effect of grouped entities, change the "Qty Random" property to 3, and change the "Max at any time" property to 4. This will randomly spawn anywhere from 1-4 of the entities and they'll be grouped together.
Hope that helped a bit.
The one and only,
~PlystirE~
Dammit, Jim! I'm a programmer not a graphic designer!!!