If you are on free edition, you probably would like to keep your events count as low as possible.
I took theubie image and remade it a little to use function object and sprite animations.
There is only one Mob sprite with four different animations "Mob1", "Mob2", "Mob3" and "Mob4".
As in theubie image i've used Local text "SpawnType" to choose("Mob1","Mob2","Mob3","Mob4"), but then instead of spawning Mob sprite equal to SpawnType variable I've called Function "spawn" with "SpawnTpe" variable as a parameter.
Function: On "spawn" spawns Mob sprite and then set proper animation by name selected from function parameter.
<img src="http://dl.dropbox.com/u/34375299/Construct%202/examples/spawn.JPG" border="0" />
It basically do the same thing like in theubie example but using less events