Especially the mass one since the convert is easy and I guess you can make freeze using SetPinField and the circular pattern algorithm but how to do the mass one?
I suppose you could make a circle and use <-x <-y 9 SetTerrain then make a smaller circle within that and do <-x <-y 1 SetTerrain. Then just do <-x <-y 0 SetCreeper and:
<-x <-y GetUnitsInRange 0 do
<-x <-y GetUnitAt ->uid
<-uid 2 Destroy
loop
something like that
You might have to use SetPinField in that area because it's a lot of operations to do in a single frame and that could affect the gameplay.