Right now im trying to use create entity at position, however it is not working,
create entity at ( get ( owner of ( last ability casting unit ) ) 's mouse cursor position ) with height ( random number between 36 and 44 ) and width ( random number between 38 and 42 ) and facing angle 0
I think casting unit is your issue here try either ‘triggering unit’ or ‘this entity’.
Casting is a legacy script so i wouldn’t recommend to use it in any current projects.
To make it easier try first to send the players name of the owner of your unit to see if the right player is found.